Leviticus 23:4-7

“ ‘These are the LORD’s appointed feasts, the holy meetings, which you will announce at the times set for them. The LORD’s Passover is on the fourteenth day of the first month, beginning at twilight. The Feast of Unleavened Bread begins on the fifteenth day of the same month. You will eat bread made without yeast for seven days. On the first day of this feast you will have a holy meeting, and you must not do any work.