Leviticus 23

15 And ye shall number to yourselves from the day after the sabbath, from the day on which ye shall offer the sheaf of the heave-offering, seven full weeks: 22 And when ye shall reap the harvest of your land, ye shall not fully reap the remainder of the harvest of your field when thou reapest, and thou shalt not gather that which falls from thy reaping; thou shalt leave it for the poor and the stranger: I am the Lord your God.