Leviticus 23:4-8
4 “These are the Lord’s appointed times, the sacred assemblies you are to proclaim at their appointed times.
5 The Passover(A) to the Lord comes in the first month, at twilight on the fourteenth day of the month.
6 The Festival of Unleavened Bread(B) to the Lord is on the fifteenth day of the same month. For seven days you must eat unleavened bread.
7 On the first day you are to hold a sacred assembly; you are not to do any daily work.
8 You are to present a fire offering to the Lord for seven days. On the seventh day there will be a sacred assembly; you must not do any daily work.”