Exodus 19:17-19 New Revised Standard Version, Anglicised Catholic Edition (NRSVACE)
17 Moses brought the people out of the camp to meet God. They took their stand at the foot of the mountain. 18 Now Mount Sinai was wrapped in smoke, because the Lord had descended upon it in fire; the smoke went up like the smoke of a kiln, while the whole mountain shook violently. 19 As the blast of the trumpet grew louder and louder, Moses would speak and God would answer him in thunder.