Deuteronomy 24:19-22

When thou cuttest down thine harvest in thy field, and hast forgot a sheaf in the field, thou shalt not go again to fetch it: it shall be for the stranger, for the fatherless, and for the widow: that the LORD thy God may bless thee in all the work of thine hands.

When thou cuttest down thine harvest. The grain pulled up by the roots or cut down with a sickle was laid in loose sheaves; the fruit of the olive was obtained by striking the branches with long poles or shaking the tree (Isaiah 17:6; Isaiah 24:13); and the grape clusters, severed by a hook, were gathered in the hands of the vintager. Here is a beneficent provision for the poor, who were to participate in the general joy at the crowning of the year with the divine goodness. Every forgotten sheaf in the harvest field was to lie; the olive tree was not to be "gone over" a second time; the shaking was the method used by the poor strangers (Harmer);-nor gleaning grapes to be gathered, in order that, in collecting what remained, the hearts of the stranger, the fatherless, and the widow might be gladdened by the bounty of Providence.