It’s a question every pastor is eventually asked. Sooner or later, someone comes up to you and asks, “Preacher, what’s the unforgivable sin?”
Occasionally, we have a good answer ready for it. Often, we don’t. It’s one of those questions many of us as pastors dread because it’s so hard to answer well.
I guess that’s why I was so relieved when I ran across St. Mark the Ascetic:
There is a sin which is always ‘unto death’ (1 John 5:16): the sin for which we do not repent. For this sin even a saint’s prayers will not be heard. (Philokalia vol. 1, 129)
Mind you, I suspect many of us have thought this before. I know I have. I’ve been giving out some variant of this answer for several years now: The only sin for which you cannot be forgiven is the sin for which you will not repent. It just feels like the right answer based on all that the Bible says.
Still, it’s kind of comforting to hear it come from someone like St. Mark the Ascetic. This is a Christian teacher living in the 400’s A.D, was thought to have been a disciple of St. John Chrysostom, and his work is preserved in one of the great spiritual anthologies of all time, the Philokalia.
I guess it’s just nice to know I have the weight of Christian tradition and history behind me when I tell people that, as long as they’ve sincerely repented, there is no sin God won’t forgive.