Leviticus 23:2-3

2“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.

The Sabbath 3“ ‘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 .