Exodus 19:11, 18, 20

and be ready against the third day; for the third day Jehovah will come down in the sight of all the people upon mount Sinai.

And mount Sinai, the whole of it, smoked, because Jehovah descended upon it in fire; and the smoke thereof ascended as the smoke of a furnace, and the whole mount quaked greatly.

And Jehovah came down upon mount Sinai, to the top of the mount: and Jehovah called Moses to the top of the mount; and Moses went up.