Exodus 19:18 KJV
And mount Sinai was altogether on a smoke, because the LORD descended upon it in fire: and the smoke thereof ascended as the smoke of a furnace, and the whole mount quaked greatly.
Exodus 19:16–20 KJV Chapter Context
16
And it came to pass on the third day in the morning, that there were thunders and lightnings, and a thick cloud upon the mount, and the voice of the trumpet exceeding loud; so that all the people that was in the camp trembled.
17
And Moses brought forth the people out of the camp to meet with God; and they stood at the nether part of the mount.
18
And mount Sinai was altogether on a smoke, because the LORD descended upon it in fire: and the smoke thereof ascended as the smoke of a furnace, and the whole mount quaked greatly.
19
And when the voice of the trumpet sounded long, and waxed louder and louder, Moses spake, and God answered him by a voice.
20
And the LORD came down upon mount Sinai, on the top of the mount: and the LORD called Moses up to the top of the mount; and Moses went up.