Leviticus 23:1-6

And the LORD spoke to Moses, saying, “Speak to the children of Israel, and say to them: ‘The feasts of the LORD, which you shall proclaim to be holy convocations, these are My feasts. ‘Six days shall work be done, but the seventh day is a Sabbath of solemn rest, a holy convocation. You shall do no work on it; it is the Sabbath of the LORD in all your dwellings. ‘These are the feasts of the LORD, holy convocations which you shall proclaim at their appointed times. On the fourteenth day of the first month at twilight is the LORD’s Passover. And on the fifteenth day of the same month is the Feast of Unleavened Bread to the LORD; seven days you must eat unleavened bread.