Deuteronomy 4:15

12 And the voice of the Lord came to you out of the fire: the sound of his words came to your ears but you saw no form; there was nothing but a voice.

13 And he gave you his agreement with you, the ten rules which you were to keep, which he put in writing on the two stones of the law.

14 And the Lord gave me orders at that time to make clear to you these laws and decisions, so that you might do them in the land to which you are going, and which is to be your heritage.

15 So keep watch on yourselves with care; for you saw no form of any sort on the day when the voice of the Lord came to you in Horeb out of the heart of the fire:

16 So that you may not be turned to evil ways and make for yourselves an image in the form of any living thing, male or female,

17 Or any beast of the earth, or winged bird of the air,

18 Or of anything which goes flat on the earth, or any fish in the water under the earth.