Leviticus 23:1-6

The LORD said to Moses, “Speak to the Israelites and say to them: ‘These are my appointed festivals, the appointed festivals of the LORD, which you are to proclaim as sacred assemblies. “ ‘There are six days when you may work, but the seventh day is a day of sabbath rest, a day of sacred assembly. You are not to do any work; wherever you live, it is a sabbath to the LORD. “ ‘These are the LORD’s appointed festivals, the sacred assemblies you are to proclaim at their appointed times: The LORD’s Passover begins at twilight on the fourteenth day of the first month. On the fifteenth day of that month the LORD’s Festival of Unleavened Bread begins; for seven days you must eat bread made without yeast.