Our justification from sins takes place at the point of saving faith, not at the point of water baptism, which usually occurs later. But if a person is already justified and has sins forgiven eternally at the point of saving faith, then baptism is not necessary for forgiveness of sins nor for the bestowal of new spiritual life. Baptism, then, is not necessary for salvation. But it is necessary if we are to be obedient to Christ, for he commanded baptism for all who believe in him.
WAYNE GRUDEM, Bible Doctrine