Lev 23:5-8

5In the first month, on the fourteenth day of the month, at twilight, there shall be a passover offering to the Lord,6and on the fifteenth day of the same month is the festival of unleavened bread to the Lord; seven days you shall eat unleavened bread.7On the first day you shall have a holy convocation; you shall not work at your occupations.8For seven days you shall present the Lord's offerings by fire; on the seventh day there shall be a holy convocation: you shall not work at your occupations.