Exodus 3:2-5

The angel of the LORD appeared to him in a blazing fire from the midst of a bush; and he looked, and behold, the bush was burning with fire, yet the bush was not consumed. So Moses said, “I must turn aside now and see this marvelous sight, why the bush is not burned up.” When the LORD saw that he turned aside to look, God called to him from the midst of the bush and said, “Moses, Moses!” And he said, “Here I am.” Then He said, “Do not come near here; remove your sandals from your feet, for the place on which you are standing is holy ground.”