Hebrews 12:25
See to it that you do not refuse Him who speaks. For if the people did not escape when they refused Him who warned them on earth, how much less will we escape if we reject Him who warns us from heaven?

Exodus 19:9
The LORD said to Moses, "Behold, I will come to you in a dense cloud, so that the people will hear when I speak with you, and they will always put their trust in you." And Moses relayed the words of the people to the LORD.

Exodus 19:19
And as the sound of the trumpet grew louder and louder, Moses spoke, and God answered him in the thunder.

Exodus 20:18
All the people witnessed the thunder and lightning, the sound of the trumpet, and the mountain in smoke. And when the people saw this, they trembled and stood at a distance.

Exodus 20:22
Then the LORD said to Moses, "This is what you are to tell the Israelites: 'You have seen for yourselves that I have spoken to you from heaven.

Deuteronomy 4:33
Has a people ever heard the voice of God speaking out of the fire, as you have, and lived?

Deuteronomy 8:5
So know in your heart that just as a man disciplines his son, so the LORD your God disciplines you.

Nehemiah 9:13
You came down on Mount Sinai, and spoke to them from heaven. You gave them just ordinances, true laws, and good statutes and commandments.