“Remember the day you stood before the LORD your God at Horeb, when the LORD said to me, ‘Assemble the people to Me, that I may let them hear My words so they may learn to fear Me all the days they live on the earth, and that they may teach their children.’ “You came near and stood at the foot of the mountain, and the mountain burned with fire to the very heart of the heavens: darkness, cloud and thick gloom. “Then the LORD spoke to you from the midst of the fire; you heard the sound of words, but you saw no form–only a voice.
Deuteronomy 4:10-12