1 Peter 2:2, “Like newborn infants, long for the pure spiritual milk, that by it you may grow up into salvation.”
The “pure spiritual milk” that Peter is talking about here is likely the “good news that was preached to you,” from chapter 1 verse 25, and the “imperishable seed” by which we have been born (Chapter 1 v.23). Peter employs a number of procreative images here…seed, birth, nursing. It is as if he is taking the “born again” concept (which he likely heared from Jesus) and unfolding the implications.
The gospel—the good news of the Son of God whose blood ransoms us from the wrath of God (1:18) and by whose resurrection we are given new life (1:3)—the gospel is not only that by and from which we are spiritually “born,” but in 2:2 it is also the ”pure spiritual milk” by which we grow up into salvation. Peter is not using “infant” here as a term for a “baby Christian,” rather according to this imagery we are ALL infants. We are ALL to be nursing from the gospel of the slain and risen Christ every single day. This—indeed, HE—is our food. Just as an infant cannot grow apart from the mother’s sustaining milk, so too the Christian cannot grow apart from daily drinking deeply from the gospel of the glory of Christ…
And what is it that causes us to continually long for the “pure spiritual milk” of the gospel? It is this: in it we have tasted and seen the all satisfying goodness of the Lord (2:3).
May we all, then, like newborn infants, long more and more for this pure spiritual milk, in which we taste and see the goodness of our God!