Exodus 19:11-20

and be ready against the third day; for the third day Jehovah will come down in the sight of all the people upon mount Sinai. And thou shalt set bounds unto the people round about, saying, Take heed to yourselves, that ye go not up into the mount, or touch the border of it: whosoever toucheth the mount shall be surely put to death: no hand shall touch him, but he shall surely be stoned, or shot through; whether it be beast or man, he shall not live: when the trumpet soundeth long, they shall come up to the mount. And Moses went down from the mount unto the people, and sanctified the people; and they washed their garments. And he said unto the people, Be ready against the third day: come not near a woman. 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. And Moses brought forth the people out of the camp to meet God; and they stood at the nether part of the mount. And mount Sinai, the whole of it, smoked, because Jehovah descended upon it in fire; and the smoke thereof ascended as the smoke of a furnace, and the whole mount quaked greatly. And when the voice of the trumpet waxed louder and louder, Moses spake, and God answered him by a voice. And Jehovah came down upon mount Sinai, to the top of the mount: and Jehovah called Moses to the top of the mount; and Moses went up.