Deuteronomy 4:10-13

10the day that thou stoodest before Jehovah thy 1God in Horeb, when Jehovah said to me, Gather me the people together, that I may cause them to hear my words, that they may learn them, and fear me all the days that they live upon the earth, and teach them to their children.

11And ye came near and stood under the mountain; and the mountain burned with fire to the heart of heaven, with darkness, clouds, and obscurity.

12And Jehovah spoke to you from the midst of the fire: ye heard the voice of the words, but ye saw no form; only [ye heard] a voice.

13And he declared to you his covenant, which he commanded you to do, the ten words; and he wrote them on two tables of stone.