Deuteronomy 4:10-13

especially concerning the day you stood before the LORD your God in Horeb, when the LORD said to me, ‘Gather the people to Me, and I will let them hear My words, that they may learn to fear Me all the days they live on the earth, and that they may teach their children.’ “Then you came near and stood at the foot of the mountain, and the mountain burned with fire to the midst of heaven, with darkness, cloud, and thick darkness. And the LORD spoke to you out of the midst of the fire. You heard the sound of the words, but saw no form; you only heard a voice. So He declared to you His covenant which He commanded you to perform, the Ten Commandments; and He wrote them on two tablets of stone.