16On the third day, when morning came, there was thunder and lightning. A thick cloud was upon the mountain, and a very loud blast of the ram's horn went out, so that all the people in the camp trembled. 17Then Moses brought the people out of the camp to meet with God, and they stood at the foot of the mountain. 18Mount Sinai was completely enveloped in smoke, because the Lord had descended on it in fire. And the smoke rose like the smoke of a furnace, and the whole mountain quaked violently. 19And as the sound of the ram's horn grew louder and louder, Moses spoke, and God answered him in the thunder. 20The Lord descended to the top of Mount Sinai and called Moses to the summit. So Moses went up, 21and the Lord said to him, 'Go down and warn the people not to break through to see the Lord, lest many of them perish. 22Even the priests who approach the Lord must consecrate themselves, or the Lord will break out against them.' 23But Moses said to the Lord, 'The people cannot come up Mount Sinai, for You solemnly warned us, 'Put a boundary around the mountain and set it apart as holy.'' 24And the Lord replied, 'Go down and bring Aaron with you. But the priests and the people must not break through to come up to the Lord, or He will break out against them.' 25So Moses went down to the people and spoke to them.