Exodus 3:1-3

1Meanwhile, Moses was shepherding the flock of his father-in-law Jethro, the priest of Midian. He led the flock to the far side of the wilderness and came to Horeb, the mountain of God.

2Then the angel of the Lord appeared to him in a flame of fire within a bush. As Moses looked, he saw that the bush was on fire but was not consumed.

3So Moses thought, “I must go over and look at this remarkable sight. Why isn’t the bush burning up?”