Exodus 31:13-17

“But as for you, speak to the sons of Israel, saying, ‘You shall surely observe My sabbaths; for this is a sign between Me and you throughout your generations, that you may know that I am the LORD who sanctifies you. Therefore you are to observe the sabbath, for it is holy to you. Everyone who profanes it shall surely be put to death; for whoever does any work on it, that person shall be cut off from among his people. For six days work may be done, but on the seventh day there is a sabbath of complete rest, holy to the LORD; whoever does any work on the sabbath day shall surely be put to death. So the sons of Israel shall observe the sabbath, to celebrate the sabbath throughout their generations as a perpetual covenant.’ It is a sign between Me and the sons of Israel forever; for in six days the LORD made heaven and earth, but on the seventh day He ceased from labor, and was refreshed.”