1 Thessalonians 5:23-24 (ESV):

23 Now may the God of peace himself sanctify you completely, and may your whole spirit and soul and body be kept blameless at the coming of our Lord Jesus Christ. 24 He who calls you is faithful; he will surely do it.


2 Peter 2:20-22 (ESV):

20 For if, after they have escaped the defilements of the world through the knowledge of our Lord and Savior Jesus Christ, they are again entangled in them and overcome, the last state has become worse for them than the first. 21 For it would have been better for them never to have known the way of righteousness than after knowing it to turn back from the holy commandment delivered to them. 22 What the true proverb says has happened to them: “The dog returns to its own vomit, and the sow, after washing herself, returns to wallow in the mire.”

Does God always faithfully fulfill his promise to completely sanctify each and every one of his Son's followers (1 Thess 5:23-24), or is it still possible for some of them to revert to their old ways (2 Peter 2:20-22)? Is there any contradiction between these two passages? What determines whether God's promise of complete sanctification will be fulfilled in the life of a Christian or not?

  • Paul is blessing "may you be sanctified and grow more that you become perfect till the end". Peter is condemning the apostates. Those who endure till the end only get saved. The condition is our faithfulness. Man fails not God. Salvation is conditional upon believers faithfulness and endurance. God has guarantee, not man.
    – Michael16
    May 18, 2021 at 17:44
  • @Michael16 - you should expand this into an answer.
    – user38524
    May 18, 2021 at 17:54

4 Answers 4


I’ll offer a response in 2 parts:

  1. The semantic range of ἁγιάζω (“hagiazó”)
  2. Application of #1 to the passages in the OP


I suggest that a one-size-fits-all definition of hagiazó (“to sanctify”) is unhelpful because it is inconsistent with the semantic range of the word found in the Bible.

The word hagiazó can describe an event that happens once (e.g. Matthew 23:17), it can describe an event that happens more than once (e.g. John 10:36, John 17:19), and it can describe a process (e.g. Ephesians 5:26)

A one-time event

“To sanctify” can refer to setting something apart for a special purpose. For example, an object can be set aside for use only in sacred rites (e.g. many of the features of Israel’s tabernacle/temples) or a person can devote him/herself to a particular cause.

This is the sense in which Jesus refers to gold as sanctified in Matthew 23:17 -- the gold does not possess special properties distinct from any other gold; it is unique because it has been set aside for religious purposes. The English verbs “to dedicate” and “to consecrate” overlap with this meaning of hagiazó “to sanctify”.

An event that happens more than once

In John 10:36 we are told that the Father sanctified Jesus (same verb, hagiazó) :

Say ye of him, whom the Father hath sanctified, and sent into the world, Thou blasphemest; because I said, I am the Son of God?

Yet a few chapters later Jesus is sanctifying Himself???

And for their sakes I sanctify myself, that they also might be sanctified through the truth. (John 17:19, same verb, hagiazó)

The Father consecrated Jesus for a specific mission; Jesus also set Himself aside--from anything and everything He might have otherwise wanted to do with His life--in order to fulfil the Father’s will. In this latter sense, Jesus “sanctified” Himself multiple times.

  • He set Himself apart from the cares & desires of the world and lived a sinless life
  • He began His ministry at about 30 years of age, starting a new phase in His life and setting Himself apart from (at least some of) that which He had done before (e.g. did He spend some of His younger years working for Joseph?)
  • He set Himself apart yet again by closing His mortal ministry and voluntarily performing the atonement

What He was doing with His life was different at age 12 vs. age 30 vs. age ~33. He had been consecrated by the Father since before the world began to do this work; but His work was not a one time event, it involved multiple steps in sanctifying Himself/setting Himself apart for a higher and holier purpose.

In hopes of not coming across in any way sacrilegious, may I suggest that as important as what Jesus did during the ~3 years of His public ministry was, what He did in the last 24 hours of His mortal life was far more important. He set Himself apart--He sanctified Himself--from a very important and monumental ministry, to perform yet an even greater task.

A Process

Biblehub provides a helpful (and admittedly concise) summary of usage of hagiazó:

make holy, treat as holy, set apart as holy, sanctify, hallow, purify

Note that even in English these words are not perfect synonyms. Sometimes hagiazó describes the process of purification--this is indeed a process, not an event. If we grant hagiazó its full semantic range we must acknowledge that sometimes it describes not the event of setting something apart but the process of purification.

Consider the Levitical sacrifices that symbolized the sacrifice of Christ:

13 For if the blood of bulls and of goats, and the ashes of an heifer sprinkling the unclean, sanctifieth to the purifying of the flesh:

14 How much more shall the blood of Christ, who through the eternal Spirit offered himself without spot to God, purge your conscience from dead works to serve the living God?

25 Nor yet that he should offer himself often, as the high priest entereth into the holy place every year with blood of others;

26 For then must he often have suffered since the foundation of the world: but now once in the end of the world hath he appeared to put away sin by the sacrifice of himself. (Hebrews 9:13-14, 25-26)

In verse 13 sanctify is used in the purify sense of the word, and it is decidedly not a one-time event--the high priest has to do it every year! The atonement of Jesus Christ then did away with the blood sacrifices--in one sacrifice Jesus brought redemption and sanctification with eternal efficacy.

So does that make sanctification (in the purification sense of the word) a one-time event now? No.

2 Beloved, now are we the sons of God, and it doth not yet appear what we shall be: but we know that, when he shall appear, we shall be like him; for we shall see him as he is.

3 And every man that hath this hope in him purifieth himself, even as he is pure. (1 John 3:2-3)

In verse 2 John addresses people who “now are” the sons of God--they’ve already been sanctified (in the setting apart sense of the word) and yet in verse 3 their purification is spoken of as an ongoing process (the verb “to purify” is in the present-indicative-active form). They are still being sanctified (in the purifying sense of the word). This should come as no surprise in the broader context of the verse--what Christian, however committed (set apart?) would claim to be today as pure as Christ is?

It is the process/purification sense of God’s work in Malachi 3 where God is compared to a refiner’s fire. Silver does not become pure because of the event of entering the fire, but because of the process of staying in the fire until the appointed time.

To put it in a more redundant form--we are sanctified, but we are not as sanctified as Jesus is. In this sense, sanctification and purification convey a spectrum, not a boolean value.

Thus Paul can use "sanctified" to refer to something that has happened in the past (such as 1 Cor. 1:2) and as something that is yet to come (as in 1 Thess 5:23).

Application to passages in the OP

The passage in 2 Peter speaks of people who have been sanctified (set apart) from the world, but apparently have not been fully sanctified (purified) from the world--there's something they haven't let go of yet. Having once been set apart from the world and consecrated to God, to fall into sin again is all the worse.

The passage in 1 Thessalonians speaks of being sanctified completely, or as rendered in the KJV (and as already noted by Dottard), sanctified wholly. Paul wants their “whole spirit and soul and body [to] be preserved blameless”.

In this sense, the “set apart” meaning of hagiazó is entirely appropriate--Paul wants everything to be consecrated, not just a little here and there when convenient. But the beauty of Paul’s statement is this: if they are sanctified/set apart wholly (holding nothing back), becoming sanctified/purified wholly is inevitable.



Does God always faithfully fulfill his promise to completely sanctify each and every one of his Son's followers

Yes, but complete sanctification carries more to it than just the act of setting apart, it involves the process of purification. If people will wholly sanctify (set apart) their lives, God will wholly sanctify (purify) them.

Or is it still possible for some of them to revert to their old ways?

Yes, people can choose to step out of the refiner’s fire at any time. I suggest that if they do so, this is strong evidence that their lives had never been wholly set apart to God. Some part of their lives had been consecrated, but that which had been left in the hands of the world overcame that which had not.

Is there any contradiction between these two passages?

No, I propose that one-step salvation is a low-cost counterfeit. The strait and narrow is a path and people can choose to depart it.

What determines whether God's promise of complete sanctification will be fulfilled in the life of a Christian or not?

Paul’s statement to the church at Thessalonica put it well--they must be “wholly sanctified”--they must be entirely committed. God will continue to refine His children until:

  • They say “no more, that’s enough” OR
  • He, the master refiner, has finished His work, and the end product is “purified, even as He is pure
  • 2
    What an Answer. With Fine quality May 12, 2022 at 21:16

The answer to this question depends on what we mean by "sanctification". The word as used in the NT is NOT a process but an even that is almost synonymous with justification.

[NOTE: the word sanctification has in modern theology a different meaning from that in the NT - its modern use is not wrong but simply different from the NT - see appendix below.]

In the NT there is no such thing as partial sanctification - one is either set apart for a special (sacred) duty or they are not. See 1 Cor 6:11 where sanctification is presented as a past completed act.

In 1 Thess 5:23 Paul discusses being "sanctified completely" - a much better translation might be "sanctified wholly" - that is in every aspect of the life. Ellicott succinctly observes:

Sanctify you wholly.—Rather, sanctify you whole. The idea is rather that of leaving no part unsanctified, than that of doing the work completely so far as it goes: thus it serves to introduce the next sentence, which explains it.

APPENDIX - Biblical Sanctification vs Theological Sanctification

In the New Testament the word “sanctification” is a translation of the Greek hagiasmos, and is equivalent to the Hebrew qadesh. Both mean holiness, consecration, sanctification, from the verb form meaning “to make holy” or “to set apart from common use”.

Let us list the relatively few occurrences of the Greek word hagiasmos: According to W E Vine , the occurrences of this noun can be classified as follows: (a) separation to God, 1 Cor 1:30, 2 Thess 2:13, 1 Peter 1:2; and (b) the course of life befitting those so separated, 1 Thess 4:3, 4, 7, Rom 6:19, 22, 1 Tim 2:15, Heb 12:14. From these, we observe that the task of sanctification is accomplished by the Holy Spirit (2 Thess 2:13, 1 Peter 1:2) and (via?) the Word.

The verb form, hagiazo, to sanctify or set apart, in the New Testament tells us that God’s sanctifying influence on the believer is via His Truth and Word (John 17:17, 19, Acts 20:32) by faith in Jesus (Acts 26:18, 1 Cor 1:2, 2 Tim 2:21, Heb 10:10, 29 ) through the Holy Spirit (Rom 15:16, 1 Cor 6:11). Note that these verbs are past tense, and discuss sanctification as a completed act (see also Heb 13:12).

However, in a few instances, the work of sanctification is set in the present as an on-going process. This process of setting apart is described as a washing of water of the Word (Eph 5:26) by the one who sanctifies (Heb 2:11, 10:14). Ceremonial sacrifices outwardly sanctify those defiled (Heb 9:13).

Thus, when a person is converted and becomes set apart for Christ (ie, becomes a Christian) the person immediately becomes a “saint” or “holy one” (Rom 1:7, 1 Cor 1:2, Phil 1:1, etc.). Sometimes these saints are called “elect” or “chosen” (Matt 24:22, 24, 31, Mark 13:20, 22, 27, Rom 11:7, 1 Tim 5:21, 2 Tim 2:10, Tit 1:1, 1 Peter 1:1), or the pure or purified (Matt 5:8; 2 Cor 11:2, Titus 1:15, 1 Peter 1:22). That is, as far as the Christian is concerned, sanctification (in the Biblical sense) occurs at conversion as a decision to follow Jesus, and occurs at some point in (past) time.

A very similar situation exists in the Old Testament where various things are set aside from common use and thus as sanctified, eg, the Sabbath, (Gen 2:3, Ex 20:11, 31:15), Israelites (Lev 19:20:7, 26, Deut 7:6, 14:2, 21, 26:19), various parts of the tabernacle (Ex 30:10, 37, 39:30) and property (Lev 27:14, 23, 28, 30, 32, Eze 48:14). Notice that such things were holy or sanctified, not because of any innate quality but by decision of man or God to set the person or object apart from common use, even a city dump (Jer 31:40).

Lastly, notice that a state of partial sanctification is unknown in the Bible – an object or person is either sanctified or it is not (1 Thess 5:23). In modern theology, the word “sanctification” is used in a quite different (extra-Biblical) sense of a growing into Christ, Christian development and character building. This is not to suggest that the idea is unbiblical, but rather that the Bible uses different terminology. That is, there is a difference between Bible sanctification and theological sanctification. Here is a sample:

  • But we know that when he appears, we shall be like him, for we shall see him as he is. Everyone who has this hope in him purifies himself, just as he is pure. 1 John 3:2, 3
  • But if anyone does not have them, he is nearsighted and blind, and has forgotten that he has been cleansed from his past sins. Therefore, my brothers, be all the more eager to make your calling and election sure. For if you do these things, you will never fall. 2 Peter 1:9, 10.

Notice the developing pattern, the saved person continues to make the decision to be one of the elect or pure by keeping separate from the world: Only let us live up to what we have already attained. Phil 3:16. This text tells us to act in accordance with our decision to follow Jesus and to be one of the “saints”.

  • But you, man of God, flee from all this, and pursue righteousness, godliness, faith, love, endurance and gentleness. Fight the good fight of the faith. Take hold of the eternal life to which you were called when you made your good confession in the presence of many witnesses. 1 Tim 6:11, 12.
  • We were therefore buried with him through baptism into death in order that, just as Christ was raised from the dead through the glory of the Father, we too may live a new life. Rom 6:4.
  • Therefore, I urge you, brothers, in view of God's mercy, to offer your bodies as living sacrifices, holy and pleasing to God--this is your spiritual act of worship. Do not conform any longer to the pattern of this world, but be transformed by the renewing of your mind. Then you will be able to test and approve what God's will is – his good, pleasing and perfect will. Rom 12:1, 2.
  • Since we have these promises, dear friends, let us purify ourselves from everything that contaminates body and spirit, perfecting holiness out of reverence for God. 2 Cor 7:1.
  • Instead, speaking the truth in love, we will in all things grow up into him who is the Head, that is, Christ. From him the whole body, joined and held together by every supporting ligament, grows and builds itself up in love, as each part does its work. Eph 4:15, 16.
  • But one thing I do: Forgetting what is behind and straining toward what is ahead, I press on toward the goal to win the prize for which God has called me heavenward in Christ Jesus. Phil 3:13, 14.
  • So then, just as you received Christ Jesus as Lord, continue to live in him, rooted and built up in him, strengthened in the faith as you were taught, and overflowing with thankfulness. Col 2:6, 7.
  • Epaphras,…is always wrestling in prayer for you, that you may stand firm in all the will of God, mature and fully assured. Col 2:12
  • His divine power has given us everything we need for life and godliness through our knowledge of him who called us by his own glory and goodness. Through these he has given us his very great and precious promises, so that through them you may participate in the divine nature and escape the corruption in the world caused by evil desires. 2 Peter 1:3, 4.
  • Therefore, dear friends, since you already know this, be on your guard so that you may not be carried away by the error of lawless men and fall from your secure position. But grow in the grace and knowledge of our Lord and Saviour Jesus Christ. 2 Peter 3:17, 18 Note the consistent pattern in scripture – continue the decision made at conversion to be sanctified (set apart) for Christ. That is, the continuing decision for Bible Sanctification results in Theological Sanctification via the miraculous work of God.

Are all followers of Christ guaranteed sanctification (1 Thess. 5:23-24 vs. 2 Peter 2:20-22)?

Answer: Sanctification is contingent upon our sustained faith (1 Jn. 1:7, 9).

That is, 1) No we are not guaranteed sanctification if we fall away (the point of 2 Pet. 2:20+), and 2) yes, we can most definitely lose our salvation if we choose to abandon it (Col. 1:23, etc.).

Suppose we read the two sets of passages together:

2 Peter 2:21-22: "For it would be better for [the apostate Christian] not to have known the way of righteousness, than having known it, to turn away from the holy commandment handed on to them. It has happened to them according to the true proverb, 'A DOG RETURNS TO ITS OWN VOMIT,' and, 'A sow, after washing, returns to wallowing in the mire.'”

1 Thessalonians 5:23-24: "Now may the God of peace Himself sanctify you entirely; and may your spirit and soul and body be preserved complete, without blame at the coming of our Lord Jesus Christ. Faithful is He who calls you, and He also will bring it to pass."

I suggested elsewhere, that the following response may be unpalatable to some. Now (as before), it is never my intent to wound those who believe we can simply never be lost once we receive salvation in Christ. However, the far greater imperative is for the truth to prevail -- something that surpasses the sensitivities of those who may disbelieve it.

It makes no difference if we add another set of passages (1 Thess. 5) to cloud the issue. This merely introduces another level of complexity. It is to the apparent misunderstanding of passages like these two which I speak. It is certainly true that, as long as we "walk in the Light" (1 Jn. 1), we are sanctified (set apart as holy) while "[our] spirit and soul and body ]is] preserved [without] blame [at Christ's return]" (1 Thess. 5:23).

Note that this pronouncement is nearly identical to Paul's words in the Letter to the Colossians:

Colossians 1:22-23: "[Christ] has now reconciled you in His fleshly body through death, in order to present you before Him holy and blameless and beyond reproach— if indeed you continue in the faith firmly established and steadfast, and not moved away from the hope of the gospel.

Here, he makes the point more emphatically. However, note the conditions upon which this holiness rests: "[If] indeed you continue in the faith firmly established and steadfast, and not moved away from the hope of the gospel." This directive could not be much clearer.

Here, allow me to point out several instances where we are told that someone can, indeed, fall away from the faith. And, in doing so, they are in a perilous condition because, no, they are no longer sanctified (set apart and purified as holy).

1. In the John's Gospel, Jesus proclaimed:

John 15:2, 6: “Every branch in Me that does not bear fruit, He takes away; and every branch that bears fruit, He prunes it so that it may bear more fruit." 6“If anyone does not abide in Me, he is thrown away as a branch and dries up; and they gather them, and cast them into the fire and they are burned" (emphasis added).

Is Christ not warning his disciples that anyone who does not abide in Him -- that is, in all His commandments, will be "gathered and cast into the fire where they are burned"? Is that fire not Hell? How else can we possibly read this? Is someone who accepted Christ and was baptized only to later decide to lead the life of an unrepentant criminal still saved, still sanctified? Has this person not, as with 2 Peter 2:20-22, metaphorically returned to "his own vomit" to "wallow in the mire"?

2. In Paul's Letter to the Galatians, the apostle warned that if these Christians continued to abandon their faith in favor of the Law of Moses, the Gospel would be useless:

Galatians 5:2: "Behold I, Paul, say to you that if you receive circumcision, Christ will be of no benefit to you" (emphasis added).

If Christ is "of no benefit" to Christians who looked back to the Old Law, how then can they be spared from eternal separation with God? This is followed by another stern warning from Paul:

Galatians 5:4: "You have been severed from Christ, you who are seeking to be justified by law; you have fallen from grace" (emphasis added).

Is not "being severed from grace" essentially the same thing as "being no longer sanctified"? Is it possible to ignore the words "severed from Christ" and "fallen from grace"? And, if we are severed or have fallen from Christ, does this not mean we are lost in eternal flames? Is there some "safety net" that will still catch the ex-Christian as they plunge headlong into Hell? If these admonitions are unconvincing, just what will ever convince someone that yes, we can fall away from the faith, no longer sanctified?

3. Perhaps the "go to" Book of the Bible in the matter of apostasy is the Letter to the Hebrews. There, we read several grave warnings:

Hebrews 2:1-3: For this reason we [Christians] must pay much closer attention to what we have heard, so that we do not drift away from it. For if the word spoken through angels proved unalterable, and every transgression and disobedience received a just penalty [in the O/T], how will we escape if we neglect so great a salvation [in Christ]?"

This passage is asking, if we "drift away" from the faith which we now possess, how will we escape the wrath of God? If I decide to denounce -- for life -- my Christianity, have I not "drifted away" from (indeed, jettisoned) my faith and sanctification? If not, how so? Are we to actually believe that God will refuse my denunciation?

4. Again, in the Letter to the Hebrews, we are cautioned never to develop faithlessness:

Hebrews 3:12: "Take care, brethren [Christians], that there not be in any one of you an evil, unbelieving heart that falls away from the living God" (emphasis added).

From this verse, the clear implication is that we can develop an evil, unbelieving heart that **falls away from God." And, if we do this, we will never enter into paradise with Him. It seems to me that to believe otherwise may constitute a certain spiritual blindness.

5. Later, in chapter 6 of the same Letter we read:

Hebrews 6:4-6: "For in the case of those who have once been enlightened and have tasted of the heavenly gift and have been made partakers of the Holy Spirit, and have tasted the good word of God and the powers of the age to come, and then have fallen away, it is impossible to renew them again to repentance, since they again crucify to themselves the Son of God and put Him to open shame" (emphasis added).

If the clause of verse 6 above ("then have fallen away") does not mean what it says, how then do words have meaning? Clearly, this passage is speaking of those who received the Gospel and were then sanctified. They "were made partakers of the heavenly gift [of Christ]," and have "fallen away" from Him. The writer then warns that it is impossible for someone in this state to be renewed as long as they persist in their present, fallen condition. Obviously, then:

Hebrews 6:8: "[If this person] yields thorns and thistles [produces worthless fruit to God], [they are] worthless and close to being cursed, and end up being burned."

How is someone in such a condition saved? Can we really employ textual gymnastics to somehow modify the meaning of the text? Or is it not the case that when someone turns to a life of willful disobedience, they are "putting the Son of God to open shame" (6:6)? As chapter 10 of the same Letter explains:

Hebrews 10:26-27: "For if we go on sinning willfully after receiving the knowledge of the truth, there no longer remains a sacrifice for sins, but a terrifying expectation of judgment and THE FURY OF A FIRE WHICH WILL CONSUME THE ADVERSARIES" (cf. Isa. 26:11, 1 Thess. 1:7, emphasis added).

There should be no doubt that if someone falls away from their faith in Christ, there is no longer any sacrifice for their sins unless they return to Him. All that is left is "a terrifying expectation of judgment."

6. Too often, we rely on the advice of those who seem to casually dismiss biblical texts of the clearest importance. Everyone should understand the meaning of 2 Peter 2 in the OP:

2 Peter 2:20-22: "For if, after they have escaped the defilements of the world by the knowledge of [Christ], they are again entangled in them and are overcome, the last state has become worse for them than the first… It has happened to them [apostates] according to the true proverb, “A DOG RETURNS TO ITS OWN VOMIT,” and, “A sow, after washing, returns to wallowing in the mire” (emphasis added).

Those who fall away from the faith are in a much more severe state than they were before they received Christ in the first place. I suggest the text of 2 Peter 2 could not be clearer in this regard.


These passages only scratch the surface of the truth that saints can fall away; 1 Thessalonians 5 adds nothing to alter the fact, as indeed is stated even more emphatically in Colossians 1:23. We should ask ourselves -- not based on someone else's opinion, -- not what we have been told, but rather on our own eyes: How do these passages (and many more) not speak directly to those who have received the gift of grace from God as stated in the verses of 1 Thessalonians 5:23-24, and have then forsaken it? Is such a person, unrepentant in their denunciation of God, really saved whatsoever? If so, how?

It is truly a wonder that anyone is unable to discern this "forest for the trees."

  • Good ans, but the detailed proof of apostasy is unnecessary, that's not the Q. Though it covered the gist indirectly. The Q post assumes Paul is giving them guarantee of sanctification; when he is only hoping n blessing them to be perfect till the end. The guarantee or assurance is conditional on our faithful. +1
    – Michael16
    May 19, 2021 at 8:38
  • 1
    @Michael16 Thanks for that. Yes, I should have been more specific to your point (and that of the OP which "assumes Paul is giving them guarantee of sanctification; when he is only hoping n blessing them to be perfect till the end." I will try to be more on point the next time (or perhaps modify this response when I have the time).
    – Xeno
    May 19, 2021 at 19:03

1 Thessalonians 5:23-24 (ESV):

23 Now may the God of peace himself sanctify you completely, and may your whole spirit and soul and body be kept blameless at the coming of our Lord Jesus Christ. 24 He who calls you is faithful; he will surely do it.

Unfortunately, some brethren were not faithful, they would fail to complete the sanctification process which led to Peter's comment in 2 Peter 2:20-22.

Does God always faithfully fulfill his promise to completely sanctify each and every one of his Son's followers?

Only if the followers do not turn their back on God.

Is it still possible for some of them to revert to their old ways (2 Peter 2:20-22)?

Yes, these are the ones who return to the entanglement of the world and overcome by the world.

What determines whether God's promise of complete sanctification will be fulfilled in the life of a Christian or not?

God is faithful but followers can still choose to turn their back on God.

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