Hebrews 5:11-12
4 “Being called,” he says, “of God an High Priest after the order of Melchisedech”: “Of whom we have many things to say and hard to be uttered [or explained].” When he was about to proceed to the difference of the Priesthood, he first reproves them, pointing out both that such great condescension was “milk,” and that it was because they were children that he dwelt longer on the lowly subject, relating to the flesh, and speaks [about Him] as about any righteous man. And see, he neither kept silence as to the doctrine altogether, nor did he utter it; that on the one hand, he might raise their thoughts, and persuade them to be perfect, and that they might not be deprived of the great doctrines; and on the other, that he might not overwhelm their minds.
“Of whom,” he says, “we have many things to say and hard to be explained, seeing you are dull of hearing.” Because they do not hear, the doctrine is “hard to be explained.” For when one has to do with men who do not go along with him nor mind the things that are spoken, he cannot well explain the subject to them.
But perhaps some one of you that stand here, is puzzled, and thinks it a hard case, that owing to the Hebrews, he himself is hindered from hearing the more perfect doctrines. Nay rather, I think that perhaps here also except a few, there are many such [as they], so that this may be said concerning yourselves also: but for the sake of those few I will speak.
Did he then keep entire silence, or did he resume the subject again in what follows; and do the same as in the Epistle to the Romans? For there too, when he had first stopped the mouths of the gainsayers, and said, “Nay but, O man, who are you that repliest against God?”, he then subjoined the solution. And for my own part I think that he was not even altogether silent, and yet did not speak it out, in order to lead the hearers to a longing [for the knowledge]. For having mentioned [the subject], and said that certain great things were stored up in the doctrine, see how he frames his reproof in combination with panegyric.
For this is ever a part of Paul's wisdom, to mix painful things with kind ones. Which he also does in the Epistle to the Galatians, saying, “You did run well; who did hinder you?” And, “Have ye suffered so many things in vain? If it be yet in vain”, and, “I have confidence in you in the Lord.” Which he says also to these [Hebrews], “But we are persuaded better things of you, and things that accompany salvation.” For these two things he effects, he does not overstrain them, nor suffer them to fall back; for if the examples of others are sufficient to arouse the hearer, and to lead him to emulation; when a man has himself for an example and is bidden to emulate himself, the possibility follows at the same time. He therefore shows this also, and does not suffer them to fall back as men utterly condemned, nor as being always evil, but [says] that they were once even good; for “when for the time ye ought to be teachers,” he says. Here he shows that they had been believers a long while, and he shows also that they ought to instruct others.
5. At all events observe him continually travailing to introduce the discourse concerning the High Priest, and still putting it off. For hear how he began: “Having a great High Priest that is passed into the heavens”; and omitting to say how He was great, he says again, “For every High Priest taken from among men, is appointed for men in things pertaining to God.” And again, “So Christ also glorified not Himself to be made an High Priest.” And again after saying, “You are a Priest for ever after the order of Melchisedech”, he again puts off [the subject], saying, “Who in the days of His Flesh offered prayers and supplications.” When therefore he had been so many times repulsed, he says, as if excusing himself, The blame is with you. Alas! How great a difference! When they ought to be teaching others, they are not even simply learners, but the last of learners., “For when for the time ye ought to be teachers, you have need again that some one teach you again which be the first principles of the oracles of God.” Here he means the Human Nature [of Christ]. For as in external literature it is necessary to learn the elements first, so also here they were first taught concerning the human nature.
You see what is the cause of his uttering lowly things. So Paul did to the Athenians also, discoursing and saying, “The times of this ignorance God winked at: but now commands all men everywhere to repent, because He has appointed a day in the which He will judge the world in righteousness by that Man whom He has ordained, whereof He has given assurance unto all men, in that He has raised Him from the dead.” Therefore, if he says anything lofty, he expresses it briefly, while the lowly statements are scattered about in many parts of the Epistle. And thus too he shows the lofty; since the very lowliness [of what is said] forbids the suspicion that these things relate to the Divine Nature. So here also the safe ground was kept.
But what produces this dullness? This he pointed out especially in the Epistle to the Corinthians, saying, “For whereas there is among you envy and strife and divisions, are you not carnal?” But observe, I beseech you, his great wisdom, how he always deals according to the distempers before him. For there the weakness arose more from ignorance, or rather from sin; but here not from sins only, but also from continual afflictions. Wherefore he also uses expressions calculated to show the difference, not saying, “you have become carnal,” but “dull”: in that case “carnal,” but in this the pain is greater. For they [the Corinthians] indeed were not able to endure [his reproof], because they were carnal: but these were able. For in saying, “Seeing you have become dull of hearing”, he shows that formerly they were sound in health, and were strong, fervent in zeal, which he also afterwards testifies respecting them.
6. “And have become such as have need of milk, not of strong meat.” He always calls the lowly doctrine “milk,” both in this place and in the other. “When,” he says, for [i.e. “because of”] the time ye ought to be teachers: because of that very thing, namely the time, for which you ought especially to be strong, for this especially you have become backsliding. Now he calls it “milk,” on account of its being suited to the more simple. But to the more perfect it is injurious, and the dwelling on these things is hurtful. So that it is not fitting that matters of the Law should be introduced now or the comparison made from them, [such as] that He was an High Priest, and offered sacrifice, and needed crying and supplication. Wherefore see how these things are unhealthful to “us”; but at that time they nourished them being by no means unhealthful to them.
So then the oracles of God are true nourishment. “For I will give unto them,” he says, “not a famine of bread, nor a thirst of water, but a famine of hearing the word of the Lord.”
“I gave you milk to drink, and not meat”; He did not say, I fed you, showing that such [nourishment] as this is not food, but that [the case is] like that of little children who cannot be fed with bread. For such have not drink given them, but their food is to them instead of drink.
Moreover he did not say, “you have need,” but “you have become such as have need of milk and not of strong meat.” That is, you willed [it]; you have reduced yourselves to this, to this need.
Source: Homilies on the Epistle to the Hebrews (New Advent)