You can't live a perfect day without doing something for someone who will never be able to repay you. John Wooden
Too great haste to repay an obligation is a kind of ingratitude. François de La Rochefoucauld
A poet ought not to pick nature's pocket. Let him borrow, and so borrow as to repay by the very act of borrowing. Examine nature accurately, but write from recollection, and trust more to the imagination than the memory. Samuel Taylor Coleridge
If you borrow some chaff from the rich man you have to repay him with wheat. Finnish Proverb
It is difficult to repay the gifts you get at a wedding or a funeral. Chinese Proverb
If you promise something it is a debt that you have to repay. Slovenian Proverb