The Greek word “huiothesia” translated “adoption” occurs five times in the N.T. (Rom.8:15, 23; 9:4; Gal.4:5; Eph.1:5); and is a compound of two words in the Greek; the first is (tithemi, G5087), which has the meaning “to assign or appoint”; the second is (huios, G5207) meaning “son”. This is the biblical theme of the (beracah) blessing of the (becorah) First born right; this motif runs throughout scripture; and it concerns abundant life, and a position of preeminence in the house of the farther, which is rewarded for being an obedient son (Gen.12:1-3; 22:16-17; 25:1; 27:3-4, 7-8, 26-38; 49:1-28;cp.37:2,14;cp.2-14;48:9-22;49:8-10;cp.44:33-45:3).The “huiothesia” takes place at the time appointed by the father; it is the time when the son is appointed as ruler over all the father’s house (Gal.4:1-2; Mt.24:45-47; cp. Rev.2:26-27; Ps.2:8-9;89:27); when he receives the blessing of the firstborn right (Rom.8:17, 29); the “reward of the inheritance” received by the matured obedient image bearing sons (Col.3:10, 23-25; cp. 1:9-12, 28).
We know from Old Testament scripture that the birth right, along with its blessing can be forfeited for disobedience (1Chron.5:1-2); to which the apostle Paul gives heed to the child of God (Eph.5:3-6), even giving examples from the O.T.(in the context of reward i.e. using words like: prize, race, run, and crown) warning us not to lose out on the inherence, as did the Israelites in the wilderness, figured by not entering the promised land (1Cor.9:24-10.1:10; Heb.12:1, 15-17).
It will be necessary to gain a proper understanding of how the word for “son” (huios) is used (in the context under consideration), being the root of “huiothesia”. In doing this, we will also look at two other words; that have different meanings in the Greek but have (like huios) been interchangeably rendered “child” or “son”. Making it difficult for the reader to see the differences of meaning, thinking they are one in the same. Which has resulted in confusing the “huiothesia” to be what takes place at the time one becomes a child of God (becoming a member of Gods family); instead of being the reward of the inheritance (Jn.3:16; Col.3:24; cp.2Tim.2:10-13).
The first word is (tekon, G5043) which should be properly rendered “child” and has the meaning of producing, to bare, to generate, and is used of one who is born; this words theological usage refers to when one becomes a child of God, upon placing faith in Christ (Jn.1:12; Rom.8:16). And has wrongly been rendered “son” in many occurrences in different bible translations, not making the distinction of when huios is being used.
Huios “son” has the meaning of being full grown, or maturity; and is used in a conditional sense (in the context under consideration), which rest upon the believers walk as being led after the spirit in obedience: “for those who are led by the spirit of God, these are the sons (huios) of God”; this speaks of the child of God who images the character and wisdom of the father, “pray for them which despitefully use you,…..that ye may be the sons (huios) of your Father which is in heaven….Be ye perfect, even as your Father which is in heaven is perfect” “But love your enemies, do good to them, and lend to them without expecting to get anything back. Then your reward will be great, and you will be sons (huios) of the Most High, because he is kind to the ungrateful and wicked. Be merciful, just as your Father is merciful.” (Rom.8:14; Mt.5:44-48; Lk.6:36).
The second word (nepios, Gr3516) has the meaning of immaturity, or adolescence, rendered “underage” (Gal.4:1, NIV) “nepios” is in contrast with “son” (being full grown), and is used of the carnal believer, as babes in Christ, not skillful in the word of God (1 Cor.3:1; Eph.4:14; Heb.5:13).
Now lets us look at the scriptures where “huiothesia" is used: Rom.8:14
For as many as are led by the Spirit of God, they are the sons (huios) of God. 15For ye have not received the spirit of bondage again to fear (of eternal judgment, under the law); but ye have received the Spirit of adoption (now having been justified from the law, now have the hope of the inheritance set before them). whereby we cry, Abba, Father. 16The Spirit itself beareth witness with our spirit, that we are the children (tekon) of God: 17and if children, then heirs; heirs of God, and joint-heirs with Christ; if so be that we suffer with him, that we may be also glorified together ….23 And not only they, but ourselves also, which have the firstfruits of the Spirit, even we ourselves groan within ourselves, waiting for the adoption, that is, the redemption of our body. For we are saved by hope: but hope that is seen is not hope: for what a man seeth, why doth he yet hope for? 25But if we hope for that we see not, then do we with patience wait for it.
Romans 8:23 clearly states, without a question of a doubt that the “huiothesia” is the future hope of the believer “waiting for the adoption (huiothesia), that is the redemption of the body". Here Paul equates the timing of the adoption to be when the body is redeemed, which takes place at the appearing of Christ (Phil.3:21).
Rom.8:23, allows us to see that the similar language in Ephesians, is indeed associating the “huiothesia” with the future hope of the believer; and is not what took place once one came to faith in Christ, and became a child of God (as entering Gods family), as it has usually been understood due to the English translation “adoption”. Let’s read in Ephesians: “Having predetermined us unto (eis) adoption” “you were sealed with the holy spirit…. which is the earnest of our inheritance until (eis) the redemption of the purchased possession” “whereby you are sealed unto (eis) the day of redemption” (Eph.1:5, 13-14, 4:30). These scriptures along with Rom.8:23 are clearly teaching that “huiothesia” is a future event that takes place at the appearing of Christ, when the believer receives his inheritance (2Tim.4:8).
Gal.4:1 Now I say, if the heir is underage (nepios), he does not differ at all from a slave although he is lord of all, 2but he is under guardians and managers until the date set by the father. 3So also we, while we were underage, were held in bondage under the elemental things of the world. 4But when the fullness of the time came, God sent forth His Son, born of a woman, born under the Law, 5So that He might redeem those who were under the Law, that we might receive the(huiothesia) adoption. 6Because you are sons, God has sent forth the Spirit of His Son into our hearts, crying, “Abba! Father!” 7Therefore you are no longer a slave, but a son; and if a son, then an heir through God.
In v.5 it says, “that we might receive the (huiothesia)” “might receive” is the Greek word (apolambano, G618) and is used in Col.3:24 “you shall receive (apolambano) the reward of the inheritance.” And in 2 Jn.1:8 “but that we receive(apolambano) a full reward”.
Here In Galatians “nepios” is used of the spiritual condition of those who were previously under the law; being servants to the spiritual powers of sin, they were in an adolescent state, or infant spiritually; and how through faith in Christ, they are now full grown “sons” ( nepious is here being used in contrast with “son”, huios); because Christ has redeemed them from the law; they are now impowered by the spirit unto perfection, no longer slaves to the powers of sin, but “sons” in Christ (Gal.1:4;3:2-3, 22; 4:1-7).
Paul is using the imagery of Israel’s servant condition still under the law covenant; with the Hellenistic cultural practice of Paul’s day, in that, while the adolescent was under guardians, until the time appointed by the father, he was no different than a slave, though lord of all. likewise in the fullness of the time, Christ came to redeem those under the law (guilty and powerless); that they may now enter the inheritance and may be lord of all (Mt.24:46-47); the end of the ages had come up them (1Cor.10:11;Rom.13:11), and they were expecting the return of Christ, and by the power of His spirit would they walk worthy of their calling (Eph.4:1), and enter the kingdom with great reward (2Pet.1:11), assigned as His ruling sons (huiothesia).
The context of one rendering themselves being dead unto sin in Romans 8, is for the reason that they may partake in the adoption on "the day of redemption" (Eph. 4:30) at the coming of Christ, that to be first to enter the Kingdom obtaining salvation with age abounding glory at the appearing of Crist (2Tim.2:10), this will be a resurrection of reward (Lu.20:35; Heb:11:35).
Redemption in this context is unto the inheritance, of How God has purchased us with the blood of Christ, for us to have the right to Gods spiritual life, generating us as His children (being born form above), for the purpose of impowering us to live as righteous sons to walk worthy of our calling, that we enter the inherence, as His ruling sons (adoption).
So, sanctification would allow one to be worthy to partake in the redemption of Gods inherence (the called-out company) that He will rule through, as themed in the Old Testament with Isarel.
We cannot be set of track from rightly dividing these truths, the unfaithful believers will not partake in the adoption, they will lose out on the inheritance of the blessing of the firstborn right. But being heirs of God, they still have the promise of life and will be raised after the thousand years, but these will not be those who partake in the first resurrection, which is a reward for obedience. Also note that each company in the bible has its own adoption, and it is also themed as a corporate event in the O.T. (cp. Rom.9:4).