EX 34:21 Sabbath Law
Six days you shall work, but on the seventh day you shall rest: in plowing time and in harvest you shall rest.
Everyone who profanes it shall surely be put to death;
For whoever does any work therein, that soul shall be cut off from among his people.
For it is a sign between me and you throughout your generations, that you may know that I am YHWH who sanctifies you.