The unforgivable sin. Bible experts don’t agree on what it is. But most agree on this much: If you’re worried that you’ve committed it and there’s no way you can get forgiven, you didn’t commit it. “If we confess our sins to God, he can always be trusted to forgive us and take our sins away,” (1 John 1:9 CEV). Bible Snapshots, p. 213.
I like this. Very short and to the point. As I understand it, the unforgivable sin is total rejection of God. If you do not believe in God, you will not feel the need to be forgiven.