Exodus 24:9-18 (ESV)
Then Moses and Aaron, Nadab, and Abihu, and seventy of the elders of Israel went up, 10 and they saw the God of Israel. There was under his feet as it were a pavement of sapphire stone, like the very heaven for clearness. 11 And he did not lay his hand on the chief men of the people of Israel; they beheld God, and ate and drank.
12 The Lord said to Moses, “Come up to me on the mountain and wait there, that I may give you the tablets of stone, with the law and the commandment, which I have written for their instruction.” 13 So Moses rose with his assistant Joshua, and Moses went up into the mountain of God. 14 And he said to the elders, “Wait here for us until we return to you. And behold, Aaron and Hur are with you. Whoever has a dispute, let him go to them.”
15 Then Moses went up on the mountain, and the cloud covered the mountain. 16 The glory of the Lord dwelt on Mount Sinai, and the cloud covered it six days. And on the seventh day he called to Moses out of the midst of the cloud. 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. 18 Moses entered the cloud and went up on the mountain. And Moses was on the mountain forty days and forty nights.