Exodus 19:11, 18, 20

and be ready for the third day. For on the third day the LORD will come down on Mount Sinai in the sight of all the people.

Now Mount Sinai was wrapped in smoke because the LORD had descended on it in fire. The smoke of it went up like the smoke of a kiln, and the whole mountain trembled greatly.

The LORD came down on Mount Sinai, to the top of the mountain. And the LORD called Moses to the top of the mountain, and Moses went up.