The bible says, Jesus died For you sins.
When we met Jesus Christ, He took our sins and moved inside of us. When you meet Jesus you are immersed into his blood and His life, You are in Christ and He is in you. The word baptism means immersed. baptism pictures: Christ dying for our sins, being buried, and resurrected.
Getting baptized is publically saying I identify with Christ. It is a picture of what Jesus has done in your life.