Exodus 20:18-19

20:18 All the people were seeing the thundering and the lightning, and heard the sound of the horn, and saw the mountain smoking – and when the people saw it they trembled with fear and kept their distance. 20:19 They said to Moses, “You speak to us and we will listen, but do not let God speak with us, lest we die.”

Hebrews 12:18-21

12:18 For you have not come to something that can be touched, to a burning fire and darkness and gloom and a whirlwind 12:19 and the blast of a trumpet and a voice uttering words such that those who heard begged to hear no more. 12:20 For they could not bear what was commanded: “If even an animal touches the mountain, it must be stoned.” 12:21 In fact, the scene was so terrifying that Moses said, “I shudder with fear.”