Mark 3:28

In solemn truth I tell you that all their sins may be pardoned to the sons of men, and all their blasphemies, however they may have blasphemed;

Matthew 12:31-32

This is why I tell you that men may find forgiveness for every other sin and impious word, but that for impious speaking against the Holy Spirit they shall find no forgiveness.

Luke 12:10

"Moreover every one who shall speak against the Son of Man, may obtain forgiveness; but he who blasphemes the Holy Spirit will never obtain forgiveness.

1 John 5:16

If any one sees a brother man committing a sin which is not unto death, he shall ask and God shall give him life--for those who do not sin unto death. There is such a thing as sin unto death; for that I do not bid him make request.

Mark 3:28-30

In solemn truth I tell you that all their sins may be pardoned to the sons of men, and all their blasphemies, however they may have blasphemed;

Hebrews 6:4-8

For it is impossible, in the case of those who have once for all been enlightened, and have tasted the sweetness of the heavenly gift, and have been made partakers of the Holy Spirit,

Hebrews 10:26-31

For if we wilfully persist in sin after having received the full knowledge of the truth, there no longer remains in reserve any other sacrifice for sins.

Treasury of Scripture Knowledge

Summary

Verily I say unto you, All sins shall be forgiven unto the sons of men, and blasphemies wherewith soever they shall blaspheme:

Bible References

General references

Matthew 12:31
This is why I tell you that men may find forgiveness for every other sin and impious word, but that for impious speaking against the Holy Spirit they shall find no forgiveness.
Luke 12:10
"Moreover every one who shall speak against the Son of Man, may obtain forgiveness; but he who blasphemes the Holy Spirit will never obtain forgiveness.
Hebrews 6:4
For it is impossible, in the case of those who have once for all been enlightened, and have tasted the sweetness of the heavenly gift, and have been made partakers of the Holy Spirit,
Hebrews 10:26
For if we wilfully persist in sin after having received the full knowledge of the truth, there no longer remains in reserve any other sacrifice for sins.
1 John 5:16
If any one sees a brother man committing a sin which is not unto death, he shall ask and God shall give him life--for those who do not sin unto death. There is such a thing as sin unto death; for that I do not bid him make request.