1 Peter 3:21

The like figure whereunto [even] baptism doth also now save
us
The ark, and deliverance by it, as it was a type of Christ, and salvation by him, so it was a figure of baptism, and baptism was the antitype of that; or there is something in these which correspond, and answer to, and bear a resemblance to each other: as the ark was God's ordinance, and not man's invention, so is baptism, it is of heaven, and not of men; and as the ark, while it was preparing, was the scorn and derision of men, so is this ordinance of the Gospel; it was rejected with disdain by the Scribes and Pharisees, as it still is by many; and as the ark, when Noah and his family were shut up in it by God, represented a burial, and they seemed, as it were, to be buried in it, it was a lively emblem of baptism, which is expressed by a burial, ( Romans 6:4 ) ( Colossians 2:12 ) and as they in the ark had the great deep broke up under them, and the windows of heaven opened over them, pouring out waters upon them, they were, as it were, immersed in, and were covered with water, this fitly figured baptism by immersion; nor were there any but adult persons that entered into the ark, nor should any be baptized but believers; to which may be added, that as the one saved by water, so does the other; for it is water baptism which is here designed, which John practised, Christ gave a commission for, and his disciples administered: it saves not as a cause, for it has no causal influence on, nor is it essential to salvation. Christ only is the cause and author of eternal salvation; and as those only that were in the ark were saved by water, so those only that are in Christ, and that are baptized into Christ, and into his death, are saved by baptism; not everyone that is baptized, but he that believeth, and is baptized, shall be saved, ( Mark 16:16 ) , for baptism

is not the putting away of the filth of the flesh;
the design of it is not to take off the sordid flesh, as circumcision did; or in a ceremonious way, outwardly, to sanctify to the purifying of the flesh, as the Jewish baptisms did; see ( Hebrews 9:10 Hebrews 9:13 ) , or to take away either original or actual sin; this only the blood of Christ can do; and it is not a mere external cleansing of the body:

but the answer of a good conscience towards God;
the Vulgate Latin renders it, "the interrogation of a good conscience"; referring, it may be, to the interrogations that used to be put to those who desired baptism; as, dost thou renounce Satan? dost thou believe in Christ? see ( Acts 8:36 Acts 8:37 ) , others render it, "the stipulation of a good conscience"; alluding also to the ancient custom of obliging those that were baptized to covenant and agree to live an holy life and conversation, to renounce the devil and all his works, and the pomps and vanities of this world; and baptism does certainly lay an obligation on men to walk in newness of life; see ( Romans 6:4 Romans 6:5 ) , the Ethiopic version renders it, "confession of God"; and to this the Syriac version agrees, rendering it, "confessing God with a pure conscience"; for, to baptism, profession of faith in Christ, and of the doctrine of Christ in a pure conscience, is requisite; and in baptism persons make a public confession of God, and openly put on Christ before men: the sense seems plainly this; that then is baptism rightly performed, and its end answered, when a person, conscious to himself of its being an ordinance of Christ, and of his duty to submit to it, does do so upon profession of his faith in Christ, in obedience to his command, and "with" a view to his glory; in doing which he discharges a good conscience towards God: and being thus performed, it saves,

by the resurrection of Jesus Christ;
being a means of leading the faith of the baptized person, as to the blood of Christ, for pardon and cleansing, so to the resurrection of Christ, to justification; see ( Acts 2:38 ) ( 22:16 ) ( Romans 4:25 ) , moreover, the sense of the passage may be this, that baptism is a like figure as the ark of Noah was; that as the entrance of Noah and his family into the ark was an emblem of a burial, so their coming out of it was a figure of the resurrection; and just such a figure is baptism, performed by immersion, both of the resurrection of Christ from the dead, and of the resurrection of saints to walk in newness of life. The Arabic version renders the whole verse thus; "of which thing baptism is now a type saving us, not by removing the filth of the flesh only, but by exhilarating a good conscience towards God, by the resurrection of Jesus Christ".