A selection of verses showing what the Bible tells us about baptism.
The apostle Peter said that baptism enables us to have our sins forgiven:
38 Peter said to them, “Repent, and be baptised, every one of you, in the name of Jesus Christ for the forgiveness of sins, and you will receive the gift of the Holy Spirit.
Our baptism into Christ is a symbolic death which links us with his death, destroying "the body of sin". It also links us with his resurrection so that we can "walk in newness of life":
3 Or don’t you know that all we who were baptised into Christ Jesus were baptised into his death? 4 We were buried therefore with him through baptism into death, that just as Christ was raised from the dead through the glory of the Father, so we also might walk in newness of life. 5 For if we have become united with him in the likeness of his death, we will also be part of his resurrection; 6 knowing this, that our old man was crucified with him, that the body of sin might be done away with, so that we would no longer be in bondage to sin.
By being baptised we put on Christ and are regarded as descendants of Abraham. We are then involved in the promises made to Abraham:
27 For as many of you as were baptised into Christ have put on Christ. 28 There is neither Jew nor Greek, there is neither slave nor free man, there is neither male nor female; for you are all one in Christ Jesus. 29 If you are Christ’s, then you are Abraham’s offspring and heirs according to promise.
We are buried with Jesus Christ by being baptised. This symbolises a burial of our old life. Coming up out of the water is a resurrection symbolising God raising us from the dead as he did Christ.
12 having been buried with him in baptism, in which you were also raised with him through faith in the working of God, who raised him from the dead. 13 You were dead through your trespasses and the uncircumcision of your flesh. He made you alive together with him, having forgiven us all our trespasses,
Baptism enables us to be saved because of the resurrection of Jesus Christ. It isn't a physical wash, but a clean conscience responding to God:
21 This is a symbol of baptism, which now saves you—not the putting away of the filth of the flesh, but the answer of a good conscience towards God, through the resurrection of Jesus Christ,
Related theme: Baptism - a first century practice