Exodus 31:17-18

Amplified Bible

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 ceased and was refreshed.”

¹⁸ When He had finished speaking with him on Mount Sinai, He gave Moses the two tablets of the Testimony, tablets of stone, written with the finger of God.