Deuteronomy 4:12-15

4:12 Then the Lord spoke to you from the middle of the fire; you heard speech but you could not see anything – only a voice was heard. 4:13 And he revealed to you the covenant he has commanded you to keep, the ten commandments, writing them on two stone tablets. 4:14 Moreover, at that same time the Lord commanded me to teach you statutes and ordinances for you to keep in the land which you are about to enter and possess.

The Nature of Israel’s God

4:15 Be very careful, then, because you saw no form at the time the Lord spoke to you at Horeb from the middle of the fire.

Deuteronomy 4:36

4:36 From heaven he spoke to you in order to teach you, and on earth he showed you his great fire from which you also heard his words.