Baptism is an important step of obedience that shows others we have personally trusted Jesus for our salvation. It is a public declaration of a personal decision to follow Jesus. When Christians are baptized, they are submerged under water to identify with the death and burial of Jesus (Romans 6:4), and raised out of the water to identify with His resurrection. You are showing people that your old spirit and your past sins are buried with Jesus, and when you come up out of the water you are saying that Jesus has given you new life.