Exodus 19:13, 16

No hand shall touch him, but he shall surely be stoned or shot through; whether beast or man, he shall not live.’ When the ram’s horn sounds a long blast, they shall come up to the mountain.”

So it came about on the third day, when it was morning, that there were thunder and lightning flashes and a thick cloud upon the mountain and a very loud trumpet sound, so that all the people who were in the camp trembled.