Mount Sinai was covered with smoke because the LORD had come down in a flaming fire. Smoke poured out of the mountain just like a furnace, and the whole mountain shook.
The LORD said to Moses, "I will come to you in a thick cloud and let the people hear me speak to you. Then they will always trust you." Again Moses reported to the people what the LORD had told him.
and the bright glory of the LORD came down and stayed there. The cloud covered the mountain for six days, and on the seventh day the LORD told Moses to come into the cloud.
Make sure that you obey the one who speaks to you. The people did not escape, when they refused to obey the one who spoke to them at Mount Sinai. Do you think you can possibly escape, if you refuse to obey the one who speaks to you from heaven?