1 John 1:10

If we say that we have not sinned, we make him a liar, and his word is not in us.

1 John 5:10

(He who believes on the Son of God, has the testimony in himself. He who believes not God, has made him a liar, because he has not believed the testimony, which God has testified concerning his Son.)

Treasury of Scripture Knowledge

Summary

That by two immutable things, in which it was impossible for God to lie, we might have a strong consolation, who have fled for refuge to lay hold upon the hope set before us:

Bible References

Impossible

1 John 1:10
If we say that we have not sinned, we make him a liar, and his word is not in us.
1 John 5:10
(He who believes on the Son of God, has the testimony in himself. He who believes not God, has made him a liar, because he has not believed the testimony, which God has testified concerning his Son.)