Which also (ο κα). Water just mentioned.

After a true likeness (αντιτυπον). Water in baptism now as an anti-type of Noah's deliverance by water. For βαπτισμα see on Matthew 3:7. For αντιτυπον see on Hebrews 9:24 (only other N.T. example) where the word is used of the earthly tabernacle corresponding (αντιτυπα) to the heavenly, which is the pattern (τυπον Hebrews 8:5) for the earthly. So here baptism is presented as corresponding to (prefigured by) the deliverance of Noah's family by water. It is only a vague parallel, but not over-fanciful.

Doth now save you (υμας νυν σωζε). Simplex verb (σωζω, not the compound διασωζω). The saving by baptism which Peter here mentions is only symbolic (a metaphor or picture as in Romans 6:2-6), not actual as Peter hastens to explain.

Not the putting away of the filth of the flesh (ου σαρκος αποθεσις ρυπου). Αποθεσις is old word from αποτιθημ (1 Peter 2:1), in N.T. only here and 2 Peter 1:14. Ρυπου (genitive of ρυπος) is old word (cf. ρυπαρος, filthy, in James 2:2; Revelation 22:11), here only in N.T. (cf. Isaiah 3:3; Isaiah 4:4). Baptism, Peter explains, does not wash away the filth of the flesh either in a literal sense, as a bath for the body, or in a metaphorical sense of the filth of the soul. No ceremonies really affect the conscience (Hebrews 9:13). Peter here expressly denies baptismal remission of sin.

But the interrogation of a good conscience toward God (αλλα συνειδησεως αγαθης επερωτημα εις θεον). Old word from επερωταω (to question as in Mark 9:32; Matthew 16:1), here only in N.T. In ancient Greek it never means answer, but only inquiry. The inscriptions of the age of the Antonines use it of the Senate's approval after inquiry. That may be the sense here, that is, avowal of consecration to God after inquiry, having repented and turned to God and now making this public proclamation of that fact by means of baptism (the symbol of the previous inward change of heart). Thus taken, it matters little whether εις θεον (toward God) be taken with επερωτημα or συνειδησεως.

Through the resurrection of Jesus Christ (δι' αναστασεως Ιησου Χριστου). For baptism is a symbolic picture of the resurrection of Christ as well as of our own spiritual renewal (Romans 6:2-6). See 1 Peter 1:3 for regeneration made possible by the resurrection of Jesus.