Luke 12:10

He who speaks against the Son of man will be forgiven. However he who blasphemes against Holy Spirit will not be forgiven.

Matthew 12:31-32

Therefore I say to you, every sin and blasphemy will be forgiven men. But the blasphemy against God's Spirit will not be forgiven.

1 John 5:16

If any man see his brother committing a sin not leading to death, he will ask, and God will give him life for them that sin not leading to death. There is a sin that leads to death. I do not say that he should make request concerning this.

1 Timothy 1:13

I was a blasphemer, and a persecutor, and a violent aggressor. I was shown mercy, because I did it ignorantly in unbelief.

Mark 3:28-30

I tell you sins will be forgiven of the sons of men, and their evil talk will be forgiven.

Luke 23:34

[Jesus said: Father, forgive them for they do not know what they do.](This verse not found in older manuscripts.) They cast lots and divided his garments among themselves.

Hebrews 6:4-8

Those who were once enlightened, and have tasted of the heavenly gift, and were made partakers of the Holy Spirit,

Hebrews 10:26-31

If we continue to (practice) (deliberately persist in) sin willfully after we have received the knowledge of the truth, there remains no more sacrifice for sins.

Treasury of Scripture Knowledge

Summary

And whosoever shall speak a word against the Son of man, it shall be forgiven him: but unto him that blasphemeth against the Holy Ghost it shall not be forgiven.

Bible References

General references

Luke 23:34
[Jesus said: Father, forgive them for they do not know what they do.](This verse not found in older manuscripts.) They cast lots and divided his garments among themselves.
Matthew 12:31
Therefore I say to you, every sin and blasphemy will be forgiven men. But the blasphemy against God's Spirit will not be forgiven.
Mark 3:28
I tell you sins will be forgiven of the sons of men, and their evil talk will be forgiven.
1 Timothy 1:13
I was a blasphemer, and a persecutor, and a violent aggressor. I was shown mercy, because I did it ignorantly in unbelief.
Hebrews 6:4
Those who were once enlightened, and have tasted of the heavenly gift, and were made partakers of the Holy Spirit,
Hebrews 10:26
If we continue to (practice) (deliberately persist in) sin willfully after we have received the knowledge of the truth, there remains no more sacrifice for sins.
1 John 5:16
If any man see his brother committing a sin not leading to death, he will ask, and God will give him life for them that sin not leading to death. There is a sin that leads to death. I do not say that he should make request concerning this.