1 John 1:9

If we confess our sins, he is faithful and just to forgive our sins, and to cleanse us from all unrighteousness.

1 John 5:16

If any one see his brother sinning a sin, not to death, let him ask, and he will grant to him life, for those who sin not to death. There is a sin leading to death. I do not say concerning it, that you should ask.

1 John 2:1-2

My little children, these things I write to you, that you may not sin. Yet if any one has sinned, we have an advocate with the Father, Jesus Christ the Just One.

Treasury of Scripture Knowledge

Summary

Wherefore I say unto you, All manner of sin and blasphemy shall be forgiven unto men: but the blasphemy against the Holy Ghost shall not be forgiven unto men.

Bible References

All

1 John 1:9
If we confess our sins, he is faithful and just to forgive our sins, and to cleanse us from all unrighteousness.
1 John 2:1
My little children, these things I write to you, that you may not sin. Yet if any one has sinned, we have an advocate with the Father, Jesus Christ the Just One.

But

1 John 5:16
If any one see his brother sinning a sin, not to death, let him ask, and he will grant to him life, for those who sin not to death. There is a sin leading to death. I do not say concerning it, that you should ask.