Exodus 16:23

16:23 He said to them, “This is what the Lord has said: ‘Tomorrow is a time of cessation from work, a holy Sabbath to the Lord. Whatever you want to bake, bake today; whatever you want to boil, boil today; whatever is left put aside for yourselves to be kept until morning.’”

Exodus 31:17

31:17 It is a sign between me and the Israelites forever; for in six days the Lord made the heavens and the earth, and on the seventh day he rested and was refreshed.’”