Leviticus 23:21-22

On this same day you shall make a proclamation as well; you are to have a holy convocation. You shall do no laborious work. It is to be a perpetual statute in all your dwelling places throughout your generations. ‘When you reap the harvest of your land, moreover, you shall not reap to the very corners of your field nor gather the gleaning of your harvest; you are to leave them for the needy and the alien. I am the LORD your God.’ ”