Leviticus 23:4-8

4These are the LORD’s appointed feasts, the sacred assemblies you are to proclaim at their appointed times. 5The Passover to the LORD begins at twilight on the fourteenth1 day of the first month. 6On the fifteenth day of the same month begins the Feast of Unleavened Bread2 to the LORD. For seven days you must eat unleavened bread. 7On the first day you are to hold a sacred assembly; you are not to do any regular work. 8For seven days you are to present a food offering to the LORD. On the seventh day there shall be a sacred assembly; you must not do any regular work.’”