Mark 3:28

Most certainly I tell you, all sins of the descendants of man will be forgiven, including their blasphemies with which they may blaspheme;

Matthew 12:31-32

Therefore I tell you, every sin and blasphemy will be forgiven men, but the blasphemy against the Spirit will not be forgiven men.

Luke 12:10

Everyone who speaks a word against the Son of Man will be forgiven, but those who blaspheme against the Holy Spirit will not be forgiven.

1 John 5:16

If anyone sees his brother sinning a sin not leading to death, he shall ask, and God will give him life for those who sin not leading to death. There is a sin leading to death. I don't say that he should make a request concerning this.

Mark 3:28-30

Most certainly I tell you, all sins of the descendants of man will be forgiven, including their blasphemies with which they may blaspheme;

Hebrews 6:4-8

For concerning those who were once enlightened and tasted of the heavenly gift, and were made partakers of the Holy Spirit,

Hebrews 10:26-31

For if we sin willfully after we have received the knowledge of the truth, there remains no more a 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
Therefore I tell you, every sin and blasphemy will be forgiven men, but the blasphemy against the Spirit will not be forgiven men.
Luke 12:10
Everyone who speaks a word against the Son of Man will be forgiven, but those who blaspheme against the Holy Spirit will not be forgiven.
Hebrews 6:4
For concerning those who were once enlightened and tasted of the heavenly gift, and were made partakers of the Holy Spirit,
Hebrews 10:26
For if we sin willfully after we have received the knowledge of the truth, there remains no more a sacrifice for sins,
1 John 5:16
If anyone sees his brother sinning a sin not leading to death, he shall ask, and God will give him life for those who sin not leading to death. There is a sin leading to death. I don't say that he should make a request concerning this.