2 Here “And” has been supplied in the translation to show clearly the connection between vv. 1 and 2.
3 Grk “getting rid of … yearn for.”
4 The word for spiritual in Greek is λογικός (logikos), which is a play on words with the reference in 1:23–25 to the living and enduring word (λόγος, logos) of God, through which they were born anew. This is a subtle indication that the nourishment for their growth must be the word of God.
5 Or “in, in regard to.” But the focus of “salvation” here, as in 1:5, 9, is the future deliverance of these who have been born anew and protected by God’s power.
6 The Byzantine text lacks εἰς σωτηρίαν (eis sōtērian, “to salvation”), while the words are found in the earliest and best witnesses (𝔓72 א A B C K P Ψ 33 81 630 1241 1505 1739 latt sy co). Not only is the longer reading superior externally, but since the notion of growing up [in]to salvation would have seemed theologically objectionable, it is easy to see why some scribes would omit it.

In other versions

Like newborn infants, long for the pure spiritual milk, that by it you may grow up into salvation—

Like newborn babies, crave pure spiritual milk, so that by it you may grow up in your salvation,

Like newborn infants, desire the pure milk of the word, so that by it you may grow up into your salvation,

Like newborn babies, you must crave pure spiritual milk so that you will grow into a full experience of salvation. Cry out for this nourishment,

like newborn infants long for the unadulterated spiritual milk, so that by it you may grow up to salvation,

As newborn babes, desire the sincere milk of the word, that ye may grow thereby:

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