Mark 3:28

I declare unto you, all the sins which men may commit, and whatsoever blasphemies they may utter, may be forgiven them.

Matthew 12:31-32

wherefore I declare to you, all manner of sin and blasphemy shall be forgiven men; but blaspheming the holy Spirit

Luke 12:10

and whoever shall cast a reflection upon the son of man, it shall be forgiven him; but as for him, that shall blaspheme the holy spirit, it shall not be forgiven.

1 John 5:16

If any man see his brother commit a sin, which is not a mortal sin, let him pray to God, who will grant him life, for such as do not commit a mortal sin. there is a sin unto death: in which case I do not enjoin any prayer to be made.

Mark 3:28-30

I declare unto you, all the sins which men may commit, and whatsoever blasphemies they may utter, may be forgiven them.

Hebrews 6:4-8

For it is impossible for those who were once enlightned, and have received the heavenly gifts, communicated by the holy spirit,

Hebrews 10:26-31

for if we wilfully apostatize, after having received the knowledge of the truth, it is as a sin for which there is no sacrifice appointed.

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
wherefore I declare to you, all manner of sin and blasphemy shall be forgiven men; but blaspheming the holy Spirit
Luke 12:10
and whoever shall cast a reflection upon the son of man, it shall be forgiven him; but as for him, that shall blaspheme the holy spirit, it shall not be forgiven.
Hebrews 6:4
For it is impossible for those who were once enlightned, and have received the heavenly gifts, communicated by the holy spirit,
Hebrews 10:26
for if we wilfully apostatize, after having received the knowledge of the truth, it is as a sin for which there is no sacrifice appointed.
1 John 5:16
If any man see his brother commit a sin, which is not a mortal sin, let him pray to God, who will grant him life, for such as do not commit a mortal sin. there is a sin unto death: in which case I do not enjoin any prayer to be made.