Leviticus 23:21-22

On this same day you shall make a proclamation, you are to have a holy convocation (calling together); you shall not do any laborious work [on that day]. It is to be a permanent statute throughout your generations wherever you may be. ‘When you reap the harvest of your land, you shall not reap to the edges of your field, nor gather the gleaning of your harvest; you are to leave them for the poor and for the stranger. I am the LORD your God.’ ”