Deuteronomy 23:19-25

Don’t charge interest to your kinsmen on any loan: not for money or food or clothing or anything else that could earn interest. You may charge foreigners interest, but you may not charge your brothers interest; that way GOD, your God, will bless all the work that you take up and the land that you are entering to possess. When you make a vow to GOD, your God, don’t put off keeping it; GOD, your God, expects you to keep it and if you don’t you’re guilty. But if you don’t make a vow in the first place, there’s no sin. If you say you’re going to do something, do it. Keep the vow you willingly vowed to GOD, your God. You promised it, so do it. When you enter your neighbor’s vineyard, you may eat all the grapes you want until you’re full, but you may not put any in your bucket or bag. And when you walk through the ripe grain of your neighbor, you may pick the heads of grain, but you may not swing your sickle there.