15 He said to the people, “Be ready for the third day. Do not approach your wives for marital relations.” 16 On the third day in the morning there was thunder and lightning and a dense cloud on the mountain, and the sound of a very loud horn; all the people who were in the camp trembled. 17 Moses brought the people out of the camp to meet God, and they took their place at the foot of the mountain. 18 Now Mount Sinai was completely covered with smoke because the Lord had descended on it in fire, and its smoke went up like the smoke of a great furnace, and the whole mountain shook violently.
1 Enoch 14:8
7 And your petition on their behalf shall not be granted, nor yet on your own: even though you weep and pray and speak all the words contained in the writing which I have written. 8 And the vision was shown to me thus: Behold, in the vision clouds invited me and a mist summoned me, and the course of the stars and the lightnings sped and hastened me, and the winds in the vision caused me to fly and lifted me upward, and bore me into heaven. 9 And I went in till I drew nigh to a wall which is built of crystals and surrounded by tongues of fire: and it began to affright me. And I went into the tongues of fire and drew nigh to a large house which was built of crystals: and the walls of the house were like a tesselated floor (made) of crystals, and its groundwork was of crystal.
Notes and References
"... the translation “mist” is based may better be rendered “dark cloud, gloom, gloomy darkness,” which would be consistent with depictions of God’s presence elsewhere (Exodus 20:21; Deuteronomy 4:11; Psalm 18:9; 97:2). Subsequent reference to lightning brings Old Testament storm-cloud theophanic descriptions to mind (Exodus 19:16; 20:18; Ezekiel 1:13–14) ..."
Heiser, Michael S. A Companion to the Book of Enoch: A Reader’s Commentary, Vol. 1 (p. 145) Defender Publishing, 2019