Leviticus 23:4-6

The Passover and the Festival of Unleavened Bread 4“ ‘These are the LORD ’s appointed festivals, the sacred assemblies you are to proclaim at their appointed times: 5The LORD ’s Passover begins at twilight on the fourteenth day of the first month. 6On the fifteenth day of that month the LORD ’s Festival of Unleavened Bread begins; for seven days you must eat bread made without yeast.