Leviticus 23:3-8

3Six days shall work be done: but on the seventh day is a sabbath of solemn rest, a holy convocation; ye shall do no manner of work: it is a sabbath unto Jehovah in all your dwellings.

4These are the set feasts of Jehovah, even holy convocations, which ye shall proclaim in their appointed season. 5In the first month, on the fourteenth day of the month at even, is Jehovah’s passover. 6And on the fifteenth day of the same month is the feast of unleavened bread unto Jehovah: seven days ye shall eat unleavened bread. 7In the first day ye shall have a holy convocation: ye shall do no servile work. 8But ye shall offer an offering made by fire unto Jehovah seven days: in the seventh day is a holy convocation; ye shall do no servile work.