"Speak also to the children of Israel, saying: "Surely My Sabbaths you shall keep, for it is a sign between Me and you throughout your generations, that you may know that I am the LORD who sanctifies you.
Exodus 31:13
Surrounding context
31:12 And the LORD spoke to Moses, saying,
31:13 "Speak also to the children of Israel, saying: "Surely My Sabbaths you shall keep, for it is a sign between Me and you throughout your generations, that you may know that I am the LORD who sanctifies you.
31:14 You shall keep the Sabbath, therefore, 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.