Baptism is a visible symbol of what happens in your heart when you place your faith in Jesus Christ. You die to your old way of living (sin) and Christ raises you to a new way of living.
For I delivered to you first of all that which I also received: that Christ died for our sins according to the Scriptures, and that He was buried, and that He rose again the third day according to the Scriptures. – 1 Corinthians 15:3-4
Therefore, we were buried with Him through baptism into death, that just as Christ was raised from the dead by the glory of the Father, even so we also should walk in the newness of life. – Romans 6:4