"If a fellow Hebrew, a man or woman sells himself to you and serves you six years, in the seventh year you must let him go free. And when you release him, do not send him away empty handed. Supply him liberally from your flock, your threshing floor and your winepress. Give to him as the Lord your God has blessed you." (
Deuteronomy 15: 12-14).
This verse speaks of a man borrowing wealth from you and when he can't repay you, you must forgive his debt and give him more before he leaves. I think it is the most clear verse that we are not to expect to be repaid for our good deeds.