Leviticus 23:5-7

“The LORD’s Passover begins at sundown on the fourteenth day of the first month. On the next day, the fifteenth day of the month, you must begin celebrating the Festival of Unleavened Bread. This festival to the LORD continues for seven days, and during that time the bread you eat must be made without yeast. On the first day of the festival, all the people must stop their ordinary work and observe an official day for holy assembly.