Exodus 24:12-18 NIV
The LORD said to Moses, “Come up to me on the mountain and stay here, and I will give you the tablets of stone with the law and commandments I have written for their instruction.”
Then Moses set out with Joshua his aide, and Moses went up on the mountain of God. He said to the elders, “Wait here for us until we come back to you. Aaron and Hur are with you, and anyone involved in a dispute can go to them.”
When Moses went up on the mountain, the cloud covered it, and the glory of the LORD settled on Mount Sinai. For six days the cloud covered the mountain, and on the seventh day the LORD called to Moses from within the cloud. To the Israelites the glory of the LORD looked like a consuming fire on top of the mountain. Then Moses entered the cloud as he went on up the mountain. And he stayed on the mountain forty days and forty nights.
NIV: New International Version