Exodus 19:16 So it came about on the third day, when it was morning, that there were thunder and lightning flashes and a thick cloud upon the mountain and a very loud trumpet sound, so that all the people who were in the camp trembled.

Exodus 19:18 Now Mount Sinai was all in smoke because the LORD descended upon it in fire; and its smoke ascended like the smoke of a furnace, and the whole mountain quaked violently.

Hebrews 12:18 For you have not come to a mountain that can be touched and to a blazing fire, and to darkness and gloom and whirlwind,

Hebrews 12:19 and to the blast of a trumpet and the sound of words which sound was such that those who heard begged that no further word be spoken to them. (NASB ©1995)