Deuteronomy 4:8-12 (ESV)
8 And what great nation is there, that has statutes and rules so righteous as all this law that I set before you today?
9 “Only take care, and keep your soul diligently, lest you forget the things that your eyes have seen, and lest they depart from your heart all the days of your life. Make them known to your children and your children's children— 10 how on the day that you stood before the Lord your God at Horeb, the Lord said to me, ‘Gather the people to me, that I may let them hear my words, so that they may learn to fear me all the days that they live on the earth, and that they may teach their children so.’ 11 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. 12 Then the Lord spoke to you out of the midst of the fire. You heard the sound of words, but saw no form; there was only a voice.