Exodus 24:12-18
24:12 The LORD said to Moses, "Come up to me on the mountain, and wait there; and I will give you the tablets of stone, with the law and the commandment, which I have written for their instruction."

24:13 So Moses set out with his assistant Joshua, and Moses went up into the mountain of God.

24:14 To the elders he had said, "Wait here for us, until we come to you again; for Aaron and Hur are with you; whoever has a dispute may go to them."

24:15 Then Moses went up on the mountain, and the cloud covered the mountain.

24:16 The glory of the LORD settled on Mount Sinai, and the cloud covered it for six days; on the seventh day he called to Moses out of the cloud.

24:17 Now the appearance of the glory of the LORD was like a devouring fire on the top of the mountain in the sight of the people of Israel.

24:18 Moses entered the cloud, and went up on the mountain. Moses was on the mountain for forty days and forty nights.