After Moses led the Israelites out of slavery in Egypt, they began a long journey through a desert wilderness. They entered the Desert of Sinai, and camped there in front of a mountain. At this place an awesome thing happened.
It started with thunder and lightning, and a thick cloud came over the mountain.
Then there was a very loud trumpet blast. (probably blown by an angel) Everyone in the camp trembled.
Then Moses led the people out of the camp to meet with God, and they stood at the foot of the mountain. Mount Sinai was covered with smoke, because the LORD descended on it in fire. The smoke billowed up from it like smoke from a furnace, the whole mountain trembled violently, and the sound of the trumpet grew louder and louder.
Then Moses spoke and the voice of God answered him. The LORD descended to the top of Mount Sinai and called Moses to the top of the mountain. So Moses went up.