Deuteronomy 4:11-13

“You came near and stood at the foot of the mountain, while flames from the mountain shot into the sky. The mountain was shrouded in black clouds and deep darkness. And the LORD spoke to you from the heart of the fire. You heard the sound of his words but didn’t see his form; there was only a voice. He proclaimed his covenant—the Ten Commandments—which he commanded you to keep, and which he wrote on two stone tablets.