Please explain Hebrews 5:14 in the simplest terms, please. Explain even those by reason of use. What does this mean?
Hebrews 5:14 NIV
But solid food is for the mature, who by constant use have trained themselves to distinguish good from evil.
According to Hebrews 5:14, there are two stages in the life of a converted Christian, whether Jew or Gentile:
the infant stage when the believer learns the basics, that is, “the rudiments of the first principles of the oracles of God” (Heb 5:12) or “the doctrine of the first principles of Christ” – Heb 6:1); and
the mature stage when the believer becomes experienced in discerning “good and evil” (Heb 5:14) or “the word of righteousness” (Heb 5:13).
The Infant Stage
This is the beginning stage of a converted believer. Apostle Peter talks about this beginning stage:
“as newborn babes desire the pure soul-nourishing milk, that you may grow by it” (1 Pet 2:2).
So, milk is not a bad thing but a good thing – for a baby in faith. But babes do not remain babes all their life time. They need to grow “to the very height of Christ’s full stature” (Eph 4:13). If they don’t grow, they are of no use to God.
The problem is that the babes in Christ are not yet spiritual but fleshly:
“And, brothers, I was not able to speak to you as to spiritual ones, but as to fleshly ones, as to babes in Christ” (1 Cor 3:1).
So, Paul gave them milk only, not solid food:
“I gave you milk to drink, and not food, for you were not then able, for neither are you yet able now. For you are yet fleshly” (1 Cor 3:2-3).
“for everyone partaking of milk is without experience in the Word of Righteousness, for he is an infant” (Heb 5:13).
So, what are “the rudiments of the beginning of the Words of God” or “the discourse of the beginning of Christ”?
The basics for the infants are (Heb 6:1-2):
“Repentance from dead works”;
“faith toward God”;
“Baptism”;
“Doctrines”;
“laying on of hands”;
“resurrection of the dead”; and
Eternal judgment”.
These are the basics of Christian life. God expects believers to grow from here to maturity.
The Mature Stage
This is the stage when the believers start taking “solid food” (Heb 5:12) instead of milk.
The mature believer has “experience in the Word of Righteousness” (Heb 5:13).
“But solid food is for those full grown, having exercised the faculties through habit, for distinction of both good and bad” (Heb 5:14).
In the mature stage a believer is adept in the Word of Righteousness which has to do with the ability to distinguish between what is good and bad.
Righteousness is dealing with grace and Law, the commandments so that the mature person does not sin habitually.
Righteousness is always contrasted with Lawlessness (or breaking of Law):
“You have loved righteousness and hated lawlessness” (Heb 1:9). “For what partnership does righteousness have with lawlessness?” (2 Cor 6:14).
There is a “Law of righteousness” (Rom 9:31).
You either “sin to death” or obey “to righteousness” (Rom 6:16).
To the mature, righteousness becomes a “habit” because since they are capable to distinguish between good and bad (through the knowledge of the Law – Rom 2:18) they can “exercise” their “faculties/ senses” (Heb 5:14).
They are ready to be “judged and corrected by the Lord” (1 Cor 11:32). They “glory in afflictions, knowing that affliction works out patience, and patience works out proven character; and proven character, hope” (Rom 5:3-4). When they are “cursed” they “bless”, when they are “persecuted” they “bear”, when they are “defamed” they “entreat” (1 Cor 4:12-13).
It is about these mature people that Jesus said: “every teacher of the Law (expert in Law of God) who becomes a disciple in the Kingdom of heaven (expert in Grace and Truth) is like a homeowner who takes new and old things out of his storage room” (Matt 13:52; GNB).
“For the Law came through Moses, but grace and truth came through Jesus Christ” (John 1:17).
The first clause is the comparison, and the second clause is the reason for the comparison.
For whereas for the time you ought to be teachers, you have need to be taught again what are the first elements of the words of God: and you are become such as have need of milk, and not of solid food. 13 For every one that is a partaker of milk, is unskillful in the word of justice: for he is a little child. 14 But solid food is for the mature; for them who by custom have their senses exercised to the discerning of good and evil.
That is, the latter clause in each case is not speaking to the metaphor (the discernment of good and evil is not talking about food being evil, nor is being unskillful in the word of righteousness anything related to babies drinking milk), but rather explaining it.
So the Christian who is so undeveloped in their spiritual journey as to still rely on teachers for the basics ("whereas for the time you ought to be teachers, you have need to be taught") is compared to someone who is still a baby drinking milk — because they rely on another for their source of food (literal milk in the case of a baby; spiritual milk in the case of people who still need "the rudimentary things of Christ" explained to them - who "need to be taught again what are the first elements of the words of God" 6:1) and someone who is a Christian on solid food is the one whom the author can go on to explain the less rudimentary things (like "repentance from dead works, teaching on baptisms and imposition of hands, resurrection from the dead" etc.) to, which he does in chapter 6.
Hebrews 5:14
But solid food is for the mature, who by constant use have trained themselves to distinguish good from evil. - NIV
The author addresses his hearers as spiritual children who cannot tell the difference between right and wrong. Thus the previous verses say:
12 By this time you ought to be teachers; you need someone to teach you the elementary truths of God’s word all over again. You need milk, not solid food! 13 Anyone who lives on milk, being still an infant, is not acquainted with the teaching about righteousness.
The writer wants these immature Christians to progress from spiritual milk to spiritual meat. So he continues in chapter 6:
Therefore let us move beyond the elementary teachings about Christ and be taken forward to maturity, not laying again the foundation of repentance from acts that lead to death, and of faith in God, 2 instruction about cleansing rites [baptism], the laying on of hands, the resurrection of the dead, and eternal judgment. 3 And God permitting, we will do so.
He isn't going to repeat the basics, which these people have already been taught. He proceeds to introduce something more advanced: the idea of Christ as the high priest of God in the order of Melchizedek.
Hebrews 8
Now the main point of what we are saying is this: We do have such a high priest, who sat down at the right hand of the throne of the Majesty in heaven, 2 and who serves in the sanctuary, the true tabernacle set up by the Lord, not by a mere human being.
Overall, the letter to the Hebrews teaches that Christians must not fall back into Jewish traditions. Instead the must recognize Christ as the true high priest who offered himself as the sacrificial offering for sin. The is the the true path to righteousness.
Conclusion: the verse cited in the OP means that these particular Christians need to grow into an adult faith. The verse helps lay the foundation for the author to instruct them about that mature understanding, as he sees it.
The Epistle of Hebrews was written to the Jewish Christians who had been studying scripture since childhood. By the time they reached middle age, they should have been teachers themselves (Heb 5:12). However, their understanding of God remained at a literal understanding, and their spiritual understanding was still in its infancy. They were not yet acquainted with the teachings about righteousness (Heb 5:13).
The NIV translation of Hebrews 5:11-14 is sub-titled "Warning Against Falling Away". To understand the context of this Epistle, it is important to note that it was written around 64 BC, during a time when the Romans authorities were persecuting Christians. Jewish Christians were under pressure to convert back to Judaism, which was a religion permitted by the Romans. This is the meaning of "Falling Away" from Christian.
Hebrews 5:14 warns immature Jewish Christian of the risk of being unable to distinguish between life and death (good from evil). It also serves as a lesson for Christians today about the importance of lifelong learning and the use of the teachings of the Lord to become spiritually mature.