Leviticus 23:6-8

Then on the fifteenth day of the same month there is the Feast of No Leavening to Yahweh; for seven days you shall eat that which is unleavened. On the first day you shall have a holy convocation; you shall not do any laborious work. But for seven days you shall present an offering by fire to Yahweh. On the seventh day is a holy convocation; you shall not do any laborious work.