Baptism is an ordinance of the church, given to us by Jesus Christ. It is a symbolic act of obedience that reminds us of not only Jesus’ baptism, but also His death, burial and ressurection. It also symbolizes our death to sin and our new life in Christ (Romans 6:4).
It is not a requirement for salvation, which is a free gift of God that comes through faith in Jesus Christ, rather it is one of teh first acts of obedience that a Christian should undertake, after accepting Jesus Christ as Savior and Lord.