Leviticus 23:3-8

3Six days shall work be done: but the seventh day is the sabbath of rest, an holy convocation; ye shall do no work in it : it is the sabbath of the LORD in all your dwellings.

4These are the feasts of the LORD, holy convocations, which ye shall proclaim in their seasons. 5In the fourteenth day of the first month at evening is the LORD’S passover. 6And on the fifteenth day of the same month is the feast of unleavened bread to the LORD: seven days ye must eat unleavened bread. 7In the first day ye shall have an holy convocation: ye shall do no servile work in it. 8But ye shall offer an offering made by fire to the LORD seven days: in the seventh day is an holy convocation: ye shall do no servile work in it .