Deuteronomy 24:18-22

But you shall remember that you were a slave in Egypt, and the LORD your God redeemed you from there; therefore I command you to do this thing. “When you reap your harvest in your field, and forget a sheaf in the field, you shall not go back to get it; it shall be for the stranger, the fatherless, and the widow, that the LORD your God may bless you in all the work of your hands. When you beat your olive trees, you shall not go over the boughs again; it shall be for the stranger, the fatherless, and the widow. When you gather the grapes of your vineyard, you shall not glean it afterward; it shall be for the stranger, the fatherless, and the widow. And you shall remember that you were a slave in the land of Egypt; therefore I command you to do this thing.