A Royal Priesthood
Priesthood Nourished by the Word of God (v. 1-3)
No new sentence begins here in the Greek text, and the connection Peter intended is probably best preserved by the NASB: ‘Therefore, putting aside (v. 1) … long for the pure milk … (v. 2).’ Peter implies that ‘putting away’ unloving practices (v. 1) is necessary for spiritual growth (v. 2), for the two verses are part of one long command. Someone who is practising ‘deceit’ or ‘envy’ or ‘slander’ will not be able truly to long for ‘pure spiritual milk’.
Priesthood Honored with Believing Worship (v. 4-8)
They are God’s dwelling place by the Spirit and his new priesthood. No internal contradiction is involved since Peter did not refer to believers as priests serving in a literal temple. The spiritual nature of the house does not draw our attention to its immateriality but to a temple inhabited by the Holy Spirit
Priesthood Called to Faithful Proclamation (v. 9-10)
God’s purpose in redeeming us is not simply our own enjoyment but that we might glorify him, as Peter indicates by the word ‘that’ in the phrase that you may declare (cf. Isa. 43:7, 25; 48:9–11; Rev. 4:11).
To declare God’s excellencies is to speak of all he is and has done. Peter’s word for ‘declare’ is not used elsewhere in the New Testament, but is used several times in the Psalms to speak of praising God (Ps. 9:14; 71:15; 73:28; 79:13; 107:22; 119:13, 26). This purpose of redemption is too often thwarted by our silence or self-congratulatory pride, but even brief association with a Christian whose speech fulfils this purpose invariably refreshes our spirits.
Priesthood Encouraged to Dedicated Obedience (v. 11-12)
Christians have no true home here on earth has been of comfort especially to those who spend years and even lifetimes away from their earthly homes in the service of Christ.
Because they are ‘aliens and exiles’ they should abstain from the passions of the flesh.