Exodus 31:15-17

LXX2012(i) 15 Six days you shall do works, but the seventh day is the sabbath, a holy rest to the Lord; every one who shall do a work on the seventh day shall be put to death. 16 And the children of Israel shall keep the sabbaths, to observe them throughout their generations. 17 It is a perpetual covenant with me and the children of Israel, it is a perpetual sign with me; for in six days the Lord made the heaven and the earth, and on the seventh day he ceased, and rested.