What does it mean that solid food is for the mature (Hebrews 5:14)?

This figure is unfolded in the next two verses. In no way is milk slighted in its due place. It is the most wholesome and suited of all nourishment for the infant; but the grown man requires quite different food for his developed state and appropriate duties. "For every one that partaketh of milk [is] unskilled (or, without experience) in the word of righteousness, for he is an infant; but solid food belongeth to full-grown persons that have by reason of habit their senses exercised for distinguishing both good and evil." By "partaking" is meant having milk for one's share in ordinary use, as a babe takes it not for partial or occasional fare, as any one might. The word translated "full-grown" is literally "perfect," and given in the A.V. so repeatedly that some lose the true force, which is simply those come to maturity.

They had become such as had need of milk instead of solid food. The Apostle does not at all slight the use of milk; but he says, If milk is the proper diet, it is a clear proof that the soul is spiritually a babe, needing to be established in the righteousness of God.

(V. 14). The stronger food — the full truth of Christianity into which the Apostle desires to lead us — belongs to the full-grown Christian, the one who is established in the position in which the righteousness of God has placed him as a son before God. Such, instead of being dull of hearing, have their senses exercised to distinguish both good and evil.

"For every one that useth milk is unskilful in the word of righteousness; for he is a babe. But solid food belong­eth to them who are of full age, even those who by reason of use have their senses exercised to discern both good and evil." It should be only briefly that we are confined to elementary principles, as a babe must be for a time confined to milk. Not that we should ever lose our taste for "the sincere milk of the Word" (1 Pet. 2:2), for even the simplest things require constant exercise and spir­itual digestion; but there must be the addition of good solid food to produce proper growth and strength. This calls for skill in the use of the Word of God, and healthy exercise of the senses in discerning between principles of good and evil. It is no mere mental stimulus or progress, but a moral and spiritual condition that is not dormant, but subject to the stirring of soul-exercise.

Of Christ, the writer had much to say to the Hebrews, but it was difficult to make it known to them because of their low state: indeed, they required the elements of Christianity rather than advanced instruction. They ought to have been teachers, but they were not skilled in the foundations, the word of righteousness; they were in need of milk, having got into a very weak spiritual condition. Solid food belongs to matured Christians, who, by habitually feeding on the word, are exercised in their spiritual sensibilities to discern what is good and what is evil.

In the closing verses of our chapter the writer gently yet firmly upbraids his Hebrew readers because they were still but babes as to their understandings when they ought to have been like full-grown men. If we make spiritual growth our spiritual senses are exercised, we acquire spiritual habits, and we become able to assimilate the "strong meat," or, "solid food," of the truth in its wider and deeper aspects. If we do not grow, though we may have received "the word of righteousness" yet we become unskilled in it. We may even slip so far back that we need to be taught over again the simplest elements concerning foundation truth.

The Hebrew Christians were in fact not going on. For the time they had been learning, they ought to have been able to teach others; but instead of that they still needed themselves to be taught, and taught the very elements. They still needed milk, rather than solid food suited for people accustomed to exercise in spiritual things, and thus educated to discern between good and evil. How much of right knowledge lies for us in this kind of discernment "The man is become as one of us, to discern good and evil." To innocence we cannot go back; and though we have got into our present condition by a fall from God, He in grace would turn it into blessing. The world, such as it is, is a place well fitted to produce and cultivate such moral discernment. If it does not this, however, it dulls and hardens the soul; and as the word of God is that which God would use to form us after His mind, the not going on with it shows this dullness of soul; and light, neglected or refused, becomes darkness.

(1) The Hebrew Christians were, in fact, not going on; at least, many were not. For the time they had been learning, they ought to have been able to teach others; but instead of that, they still needed themselves to be taught, and taught the very elements. They still needed milk, and could not digest "solid food." It is not "strong meat," an expression which has been very much abused, as if it were something requiring extra spiritual power to digest it. It is simply that which is suited for people accustomed to be exercised indeed in spiritual things, and thus educated so as to discern between good and evil. How much of right knowledge lies for us in this kind of discernment! "The man has become as one of us, to discern good and evil." To innocence we cannot go back; and though we have got into our present condition by a fall from God, He, in grace, would turn even this into blessing. The world, such as it is, is a place well fitted to produce and to cultivate such moral discernment. If it does not do this, however, it dulls and hardens the soul; and as the Word is that which God would use to form us after His mind, the not going on with it at once tends to increase in us this dullness of soul.

He prays for discernment (judgment). Sometimes this may signify a “spiritual sense of smell,” or “taste;” but here it has the sense of taste for judgment, discernment, reason. Paul prays for the Philippians in chapter one verse 10: “That ye may approve things that are excellent,” or as the N.I.V. puts it: “ … so that you may be able to discern what is best … ” For the believer it is not a question of refusing sin or sinful things, but of discerning what is profitable and constructive, and what is not. Good judgment and knowledge are essential for spiritual growth. “ … but solid food belongs to full-grown men, who, on account of habit, have their senses exercised for distinguishing both good and evil” (Heb. 5:14). Now this kind of spiritual discernment does not come to us automatically, as we learn from the verse in Hebrews 5. It comes with practise. That is why the writer begins this verse 66 with: “Teach me … ” Are we willing to be taught?

The corresponding adjective is translated "of full age" (Heb. 5:14) simply, meaning "maturity" in contrast to the state under the Jewish system which was occupied with "the first principles" or rudiments" of the "oracles of God" or of the "doctrine of Christ." The Hebrews were encouraged to go on to perfection, i.e., to the apprehension of Christ in glory. Judaism, i.e., ritualism, never could effect that end. They had not even got the question of righteousness settled in their souls and were necessarily inexperienced in the word of righteousness. The further method of discernment was quite beyond them. The Holy Spirit's presence consequent on Christ's exaltation and glory is the factor which sharpens our senses or spiritual faculties to discriminate between subtle distinctions of good and evil. This is much more comprehensive than what man describes as morality or conduct.

To seek counsel as to whether a thing be evil, and still to seek counsel when we know it is evil, are two acts altogether distinct. Not only may we ask of the Lord to give us discernment as to evil, but more, this is without contradiction a duty it behoves us sedulously and with honesty to fulfil. Scripture tells us that this discernment is a distinctive characteristic of "those who are of full age." (Heb. 5:14.)