Originally Answered: What does Peter mean in 1 Peter 3:21 that "baptism" saves us?
He said it because “baptism saves”. (What would he have said if he had meant "baptism saves"?)
This verse in the New American Standard Bible says, “Corresponding to that, baptism now saves you -- not the removal of dirt from the flesh, but an appeal to God for a good conscience – through the resurrection of Jesus Christ.”
The English Standard Version says, “Baptism, which corresponds to this, now saves you, not as a removal of dirt from the body but as an appeal to God for a good conscience, through the resurrection of Jesus Christ.”
(These are two of the most accurate English translations of the Bible.)
Baptism is a command of Christ. He said, “He that believes and is baptized shall be saved.” (Mark 16:16)
Many will tell you that someone believes, is saved, and then he shall be baptized. This is not the same thing Jesus said. It is not in the same order.
What would Jesus have said if he had meant, “He that believes and is baptized shall be saved”? I believe he said what he meant and meant what he said. I believe Jesus! “He that believes not shall be condemned.” (Mark 16:16)
Many agree that baptism is commanded by Christ, but they say it is not necessary for salvation. Hebrews 5:9 says, “He became the author of eternal salvation unto all them that obey him.” It is necessary to obey Christ to be saved!
Acts 2:38 says that baptism is “for the remission of sins”, “unto the remission of sins” or “so that your sins will be forgiven”. (Depending on which translation you read.) I Peter 3:21 says "baptism now saves"!
In the conversion of Saul (Paul), Acts 22:16 says he was commanded to be baptized and wash away his sins. Can we be saved if our sins remain? The blood of Christ washes away sins (Revelation 1:5) .
Romans 6:3-4 says we are “baptized into Christ”. Can we be saved outside of Christ? (See Gal. 3:27 also.) These verses in Romans also say we are “baptized into his death”. At Christ’s death is where his saving blood was shed and offered for our sins. We must contact His death to contact that blood! Can we be saved if we have not contacted His death?
Romans 6:3-4 also say that at baptism we “rise to walk in newness of life.” At a birth there is a new life. Can we be saved if we have not been “born again” to this new life?
In the New Testament after Jesus gave the command about baptism, every example of a conversion specifically mentions baptism. None of these converts ate, drank, slept, or continued their journey until they were baptized. It was always immediate.
Some point to examples, such as the thief on the cross, before Jesus issued his command of baptism. They could not have obeyed a command that had not yet been issued. Also the death, burial, and resurrection that baptism now represents had not occurred at that time. How could they be baptized into Christ's death, when Christ had not yet died?
Those before Christ's death lived under the Old Testament. The New Testament came into effect after Christ died and rose again. (Hebrews 9:15-17) And remember, it was after His death that he commanded baptism (Mark 16:16, Matt. 28:18-20) All those who now live after that point in time are subject to the New Testament and to that command.
Also, the thief on the cross was at the scene of Christ's crucifixion. He had direct contact with Christ at His death. We are not in that position. Again, it is through baptism that we contact His death!
Saul who I mentioned earlier, is a good example of the necessity of baptism. He spoke to Jesus. He called Jesus “Lord” and he asked what he needed to do to be saved. Jesus told him to go into the city and it would be told to him what he “must do”. In the city he fasted for three days and he was praying. (Acts 9:9-11) Many would say he was saved at that point, but he still had not been told what he “must do”.
Then he was told to be baptized and wash away his sins. Please note, even though he had not eaten or drank for three days, he was baptized before he took food. (Acts 9:18-19) This shows the urgency of baptism. In fact, none of the new converts in the book of Acts ate, drank, slept or continued a journey until they had been baptized!
Baptism is specifically mentioned in all of these examples. Love, grace, mercy, confession, repentance, and the blood of Christ are all necessary for salvation, but they are not specifically mentioned every time, but baptism is!
After one believes, repents and confesses Christ; baptism is the point at which we come “into Christ”. The act of being immersed in water and rising up out of the water symbolically recreates Christ's death, burial, and resurrection. It is this way God has appointed for us to contact Christ's death and be forgiven of our sins. Baptism is “for the remission of sins"!
"And now why tarriest thou? arise, and be baptized, and wash away thy sins, calling on the name of the Lord!" (Acts 22:16)