Deuteronomy 23:19-25

Do not charge a fellow Israelite interest, whether on money or food or anything else that may earn interest. You may charge a foreigner interest, but not a fellow Israelite, so that the LORD your God may bless you in everything you put your hand to in the land you are entering to possess. If you make a vow to the LORD your God, do not be slow to pay it, for the LORD your God will certainly demand it of you and you will be guilty of sin. But if you refrain from making a vow, you will not be guilty. Whatever your lips utter you must be sure to do, because you made your vow freely to the LORD your God with your own mouth. If you enter your neighbor’s vineyard, you may eat all the grapes you want, but do not put any in your basket. If you enter your neighbor’s grainfield, you may pick kernels with your hands, but you must not put a sickle to their standing grain.