Exodus 31:17 in the World English Bible
It is a sign between me and the children of Israel forever; for in six days the LORD made heaven and earth, and on the seventh day he rested, and was refreshed.’”
Context
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 the LORD made heaven and earth, and on the seventh day he rested, and was refreshed.
18 And he gave unto Moses, when he had made an end of communing with him upon mount Sinai, two tables of testimony, tables of stone, written with the finger of God.