1 Peter 2:2

2.The sincere milk of the word This passage is commonly explained according to the rendering of Erasmus, “Milk not for the body but for the soul;” as though the Apostle reminded us by this expression that he spoke metaphorically. I rather think that this passage agrees with that saying of Paul,

“Be ye not children in understanding, but in malice.”
(1 Corinthians 14:20.)

That no one might think that infancy, void of understanding and full of fatuity, was commended by him, he in due time meets this objection; so he bids them to desire milk free from guile, and yet mixed with right understanding. We now see for what purpose he joins these two words, rational and guileless, ( λογικὸν καὶ ἄδολος.) For simplicity and quickness of understanding are two things apparently opposite; but they ought to be mixed together, lest simplicity should become insipid, and lest malicious craftiness should creep in for want of understanding. This mingling, well regulated, is according, to what Christ says,

“Be ye wise as serpents, and harmless as doves.”
(Matthew 10:16.)

And thus is solved the question which might have been otherwise raised. (19)

Paul reproves the Corinthians because they were like children, and therefore they could not take strong food, but were fed with milk. (1 Corinthians 3:1.) Almost the same words are found in Hebrews 5:12. But in these passages those are compared to children who remain always novices and ignorant scholars in the doctrine of religion, who continued in the first elements, and never penetrated into the higher knowledge of God. Milk is called the simpler mode of teaching, and one suitable to children, when there is no progress made beyond the first rudiments. Justly, then, does Paul charge this as a fault, as well as the author of the Epistle to the Hebrews. But milk, here, is not elementary doctrine, which one perpetually learns; and never comes to the knowledge of the truth, but a mode of living which has the savor of the new birth, when we surrender ourselves to be brought up by God. In the same manner infancy is not set in opposition to manhood, or full age in Christ, as Paul calls it in Ephesians 4:13, but to the ancientness of the flesh and of former life. Moreover, as the infancy of the new life is perpetual, so Peter recommends milk as a perpetual aliment, for he would have those nourished by it to grow.