Leviticus 23:2-3

Thomson(i) 2 Speak to the children of Israel, and thou shalt say unto them, With respect to the festivals of the Lord, which you shall proclaim holy, set days; these are my festivals. 3 Six days thou shalt perform works, but on the seventh day are sabbaths, a solemn rest dedicated to the Lord, thou shalt not do any work. Sabbaths are for the Lord in all your dwellings.