Deuteronomy 24:20-22

20When thou beatest thine olive tree, thou shalt not go over the boughs again: it shall be for the stranger, for the fatherless, and for the widow.1

21When thou gatherest the grapes of thy vineyard, thou shalt not glean it afterward: it shall be for the stranger, for the fatherless, and for the widow.2

22And thou shalt remember that thou wast a bondman in the land of Egypt: therefore I command thee to do this thing.