Deuteronomy 5:2

5:2 The Lord our God made a covenant with us at Horeb.

Exodus 19:9

19:9 The Lord said to Moses, “I am going to come to you in a dense cloud, so that the people may hear when I speak with you and so that they will always believe in you.” And Moses told the words of the people to the Lord.

Exodus 19:16

19:16 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.

Exodus 20:18

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.

Hebrews 12:18-19

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.

Hebrews 12:25

12:25 Take care not to refuse the one who is speaking! For if they did not escape when they refused the one who warned them on earth, how much less shall we, if we reject the one who warns from heaven?