Leviticus 23:3-7

‘For six days work may be done, but the seventh day is the Sabbath of complete rest, a holy convocation (calling together). You shall not do any work [on that day]; it is the Sabbath of the LORD wherever you may be. ‘These are the appointed times of the LORD, holy convocations which you shall proclaim at their appointed times: The LORD’S Passover is on the fourteenth day of the first month at twilight. The Feast of Unleavened Bread to the LORD is on the fifteenth day of the same month; for seven days you shall eat unleavened bread. [1 Cor 5:7, 8] On the first day you shall have a holy convocation (calling together); you shall not do any laborious work [on that day].