Exodus 19:15-17

Young's Literal Translation

¹⁵ and he saith unto the people, `Be ye prepared for the third day, come not nigh unto a woman.'

¹⁶ And it cometh to pass, on the third day, while it is morning, that there are voices, and lightnings, and a heavy cloud, on the mount, and the sound of a trumpet very strong; and all the people who [are] in the camp do tremble.

¹⁷ And Moses bringeth out the people to meet God from the camp, and they station themselves at the lower part of the mount,