text: what is the purpose of water baptism? what does this passage mean and how does it fit in with salvation?  "when the people heard this, they were cut to the heart and said to peter and the other apostles, "brothers, what shall we do?"  peter replied, "repent and be baptized, every one of you, in the name of jesus christ for the forgiveness of your sins. and you will receive the gift of the holy spirit.the promise is for you and your children and for all who are far off—for all whom the lord our god will call." the purpose and result of baptism varies from denomination to denomination. for some, it is a guarantee of an afterlife; for others it is a symbolic cleansing of past sins, and a symbol of being born again.  or it can be thought of as a combination of these ideas.  the idea of baptism in the christian tradition comes out of the jewish system of ritual bathing in a mikveh for ceremonial impurity.  individuals who violated the laws of purity by touching a  corpse, blood or anything designated unclean, were to bath in a souce of "living water" --fresh running water in order to remove the impurity.  here is a website that talks about this jewish ritual: