Deuteronomy 4:11-13

And you came near and stood at the foot of the mountain, while the mountain burned with fire to the heart of heaven, wrapped in darkness, cloud, and gloom. Then the Lord spoke to you out of the midst of the fire...

'The Giving of the Law from Mt. Sinai', drawing by W. G. Phillips, engraving by Alonzo Chappel. My own colorisation.