There the angel of the LORD 1 appeared to him in flames of fire2 from within a bush.3 Moses saw that though the bush was on fire it did not burn up.
References for Exodus 3:2
So Moses thought, "I will go over and see this strange sight--why the bush does not burn up."
When the LORD saw that he had gone over to look, God called4 to him from within the bush,5 "Moses! Moses!" And Moses said, "Here I am."6
References for Exodus 3:4