Baptism is the public declaration of a personal commitment to follow Christ. 

Baptism is a symbolic act that demonstrates that our sins have been washed away through the blood of Christ shed for us on the cross (1 Peter 1:18-19).  It demonstrates that we have died to sin (so it no longer has power over us) and we have been resurrected to new life in Christ (Romans 6:4; 2 Corinthians 5:17).