The act of submerging under water and returning to the surface is an act of identifying with Christ. This shows what has occurred in the lives of the believer. It’s an act of obedience
That gives testimony to what spiritually occured in our lives. We have gone from death to life.
Any person who has made a commitment to give their lives to follow Christ, be obedient to the word of God and live a new life, is a candidate for baptism. Such people have repented of their sins and are ready to receive God.
No. The bible teaches us that only the blood of Christ can clean our sins. (Romans 5: 8,9; 1John 1:7) But if we want to receive the benefits of his sacrifice, we should have faith in Jesus, change our way of life. (Jobs 2:38; 3:19)