And when morning came on the third day, there were thunders and flames and a thick cloud on the mountain, and a horn sounding very loud; and all the people in the tents were shaking with fear.

He is not to be touched by a hand, but is to be stoned or have an arrow put through him; man or beast, he is to be put to death: at the long sounding of a horn they may come up to the mountain.

And when the sound of the horn became louder and louder, Moses' words were answered by the voice of God.