The following is taken from Word Studies in the Greek New Testament by Kenneth S. Wuest
The words the like figure are in the Greek ho antitupon. The question as to whether the word figure refers back to the word ark or the word water, is easily settled by the Greek grammar involved in this expression, for the relative pronoun ho is neuter, the word ark is feminine, and the word water neuter. The relative pronoun agrees with its antecedent in gender. Therefore the word figure which is neuter and construed grammatically with the pronoun ho goes back to the word water. The word figure is the translation of antitupon which means the counterpart of reality. The Greek word baptism is in apposition with the word figure. Our translation so far reads, Which (water) also (as a) counterpart now saves you, (namely) baptism. Water baptism is clearly in the apostles mind, not the baptism by the Holy Spirit, for he speaks of the waters of the flood as saving the inmates of the ark, and in this verse, of baptism saving believers. But he says that it saves them only as a counterpart. That is, water baptism is the counterpart of the reality, salvation. It can only save as a counterpart, not actually. The Old Testament sacrifices were counterparts of the reality, the Lord Jesus. They did not actually save the believer, only in type. It is not agued here that these sacrifices are analogous to Christian water baptism. The author is merely using them as an illustration of the use of the word counterpart. So water baptism only saves the believer in type. The Old Testament Jew was saved before he brought the offering. That offering was only his outward testimony that he was placing his faith in the Lamb of God of whom these sacrifices were a type. The moment he conceived in his heart that he would bring his offering to the tabernacle, his faith leaped the centuries to the time when God would offer the Sacrifice that would pay for his sin. Our Lord said, Abraham rejoiced to see my day: and he saw it, and was glad (John 8:56) the act of bringing the sacrifice was his outward expression and testimony of his inward faith. Water baptism is the outward testimony of the believers inward faith. The person is saved the moment he places his faith in the Lord Jesus. Water baptism is his visible testimony to his faith and the salvation he was given in answer to that faith.
Peter is careful to inform his readers that he is not teaching baptismal regeneration, namely, that a person who submits to baptism is thereby regenerated, for he says, not the putting away of the filth of the flesh. Baptism, Peter explains, does not wash away the filth of the flesh, either in a literal sense as a bath for the body, nor in a metaphorical sense as a cleansing fro the soul. No ceremonies really affect the conscience. But he defines what he means by salvation, in the words the answer of a good conscience toward God, and he explains how this is accomplished, namely by the resurrection of Jesus Christ in that the believing sinner is identified with Him in that resurrection.
Fuller translation
. (18) Because Christ also died once for all in relation to sins, as just One on behalf of unjust ones, in order that He might provide you with an entrée into the presence of God, having in fact been put to death with respect to the flesh, but made alive with respect to the spirit, (19) in which (human spirit) also proceeding, He made proclamation to the spirits in prison (20) who were at one time rebels when the longsuffering of God waited out to the end in the days of Noah while the ark was being made ready; in which eight sols were brought safely through by means of the intermediate agency of water, (21) which (water) as a counterpart now saves you, (namely) baptism; not putting off of filth of flesh, but the witness of a good conscience toward God, through the resurrection of Jesus Christ (22) who is at the right hand of God, having proceeded into heaven, there having been made subject to Him, angels, and authorities, and powers.
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