Now Moses was keeping the flock of his father-in-law, Jethro, the priest of Mid′ian; and he led his flock to the west side of the wilderness, and came to Horeb, the mountain of God. And the angel of the Lord appeared to him in a flame of fire out of the midst of a bush; and he looked, and lo, the bush was burning, yet it was not consumed. And Moses said, “I will turn aside and see this great sight, why the bush is not burnt.” When the Lord saw that he turned aside to see, God called to him out of the bush, “Moses, Moses!” And he said, “Here am I.” Then he said, “Do not come near; put off your shoes from your feet, for the place on which you are standing is holy ground.” And he said, “I am the God of your father, the God of Abraham, the God of Isaac, and the God of Jacob.” And Moses hid his face, for he was afraid to look at God.
Exodus 3:1-6