Forgiveness of Sin
Jesus calls the people “Repent and Baptise in the name of Jesus Christ”.
Sins committed before once’s conversion are forgiven during the baptism ritual, which is effectively executed after an individual has repented: only then the baptism shall be ‘received’.
But sins committed after baptism (would this be possible) shall not be forgiven, only transgressions:
HEB 10: 26 For if we sin wilfully after that we have received the knowledge of the truth, there remaineth no more sacrifice for sins,
HEB 10: 27 But a certain fearful looking for of judgment and fiery indignation, which shall devour the adversaries.
The best which those who consciously sin after their baptism (would this be possible) can hope for is the exemptional pardon Jesus has granted to the thief by his side, whilst on the cross.
LUK 23: 42 And he said unto Jesus, Lord, remember me when thou comest into thy kingdom.
LUK 23: 43 And Jesus said unto him, Verily I say unto thee, To day shalt thou be with me in paradise.
Forgiveness of transgressions comes through a contrite heart: truly repenting what you have done and praying for forgiveness. But, as baptism is described as a rebirth of incorruptible seed, one can only conclude that reverting to sin after baptism is impossible.
JOH 3: 3 Jesus answered and said unto him, Verily, verily, I say unto thee, Except a man be born again, he cannot see the kingdom of God.
JOH 3: 7 Marvel not that I said unto thee, Ye must be born again.
PE1 1: 23 Being born again, not of corruptible seed, but of incorruptible, by the word of God, which liveth and abideth forever.