Exodus 31:15-17

American Standard Version

¹⁵ 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. ¹⁶ Wherefore the children of Israel shall keep the sabbath, to observe the sabbath throughout their generations, for a perpetual covenant. ¹⁷ 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.