Exodus 31:12-18

And Jehovah spake unto Moses, saying, Speak thou also unto the children of Israel, saying, Verily ye shall keep my sabbaths: for it is a sign between me and you throughout your generations; that ye may know that I am Jehovah who sanctifieth you. Ye shall keep the sabbath therefore; for it is holy unto you: every one that profaneth it shall surely be put to death; for whosoever doeth any work therein, that soul shall be cut off from among his people. Six days shall work be done, but on the seventh day is a sabbath of solemn rest, holy to Jehovah: whosoever doeth any work on the sabbath day, he shall surely be put to death. Wherefore the children of Israel shall keep the sabbath, to observe the sabbath throughout their generations, for a perpetual covenant. It is a sign between me and the children of Israel for ever: for in six days Jehovah made heaven and earth, and on the seventh day he rested, and was refreshed. And he gave unto Moses, when he had made an end of communing with him upon mount Sinai, the two tables of the testimony, tables of stone, written with the finger of God.