Exodus 19:15-17 American Standard Version (ASV)
15 And he said unto the people, Be ready against the third day: come not near a woman.
16 And it came to pass on the third day, when it was morning, that there were thunders and lightnings, and a thick cloud upon the mount, and the voice of a trumpet exceeding loud; and all the people that were in the camp trembled. 17 And Moses brought forth the people out of the camp to meet God; and they stood at the nether part of the mount.
Exodus 19:15-17 New International Version (NIV)
15 Then he said to the people, “Prepare yourselves for the third day. Abstain from sexual relations.”
16 On the morning of the third day there was thunder and lightning, with a thick cloud over the mountain, and a very loud trumpet blast. Everyone in the camp trembled. 17 Then Moses led the people out of the camp to meet with God, and they stood at the foot of the mountain.