Exodus 31:12-15

12And the Lord spoke to Moses, saying,

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.

14You 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.

15Work shall be done for six days, but the seventh is the Sabbath of rest, holy to the Lord. Whoever does any work on the Sabbath day, he shall surely be put to death.