DEU 24:19

19 When thou cuttest down thine katzir in thy sadeh, and hast forgot an omer [(sheaf)] in the sadeh, thou shalt not go again to bring it back; it shall be for the ger, for the yatom [(orphan)], and for the almanah; that Hashem Eloheicha may bless thee in all the ma'aseh of thine hands.