Let me know what penance I owe you.
The only definitions I can find for the word "penance" are religious terms that imply that one has sinned and must somehow repent or make up for it to God or clergy.
What is meant by "owing penance" to another (non-clerical) human being, in this context?
Edit: Since I've gotten some downvotes for this question, I wonder if those who downvoted could help me improve it by explaining why they did so. (E.G. poorly researched, unclear, off-topic, offensive, general reference, inaccurate assumptions, etc.) Although it's not required, it's always more helpful if downvotes come coupled with constructive feedback.