When we believe the Gospel preached by Jesus Christ we are required:
1. To repent of our sinful way of life (which means to change the way we live).
Acts 3:19 Repent ye therefore, and be converted, that your sins may be blotted out, when the times of refreshing shall come from the presence of the Lord;
2. To be baptised by immersion in water for the forgiveness of past sins.
Acts 2:38 Then Peter said unto them, Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins…
Acts 22:16 And now why tarriest thou? arise, and be baptized, and wash away thy sins, calling on the name of the Lord.
3. To live a new life by the commandments of Jesus Christ.
Romans 6:4 Therefore we are buried with him by baptism into death: that like as Christ was raised up from the dead by the glory of the Father, even so we also should walk in newness of life.
John 15:13 Greater love hath no man than this, that a man lay down his life for his friends. 14 Ye are my friends, if ye do whatsoever I command you.
Luke 6:46 And why call ye me, Lord, Lord, and do not the things which I say?
James 1:22 But be ye doers of the word, and not hearers only, deceiving your own selves.
Jesus is the ‘light of the world’ and to live by Christ’s commandments is to ‘walk in the light’. However, after baptism, we cannot live a sinless life, but providing we are making a determined effort to live by Christ’s commandments our sins will be forgiven by confession in prayer.
1 John 1:7-9 But if we walk in the light, as he is in the light, we have fellowship one with another, and the blood of Jesus Christ his Son cleanseth us from all sin. 8 If we say that we have no sin, we deceive ourselves, and the truth is not in us. 9 If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness.
We have this assurance for sins committed through the weakness of our flesh.
1 John 2:1 My little children, these things write I unto you, that ye sin not. And if any man sin, we have an advocate with the Father, Jesus Christ the righteous:
This doesn’t mean that we can deliberately carry on sinning.
Hebrews 10:26 (NIV) If we deliberately keep on sinning after we have received the knowledge of the truth, no sacrifice for sins is left,
Galatians 6:7 Be not deceived; God is not mocked: for whatsoever a man soweth, that shall he also reap.
From this we understand that sins committed through weakness will be forgiven, but sins committed on the presumption that God will forgive fall into a different category. Sin calls for self-examination in the light of the Gospel.
I hope you find this helpful.