Exodus 3:2-5

There the angel of the LORD appeared to him in flames of fire coming out of a bush. Moses saw that the bush was on fire, but it was not burning up. So he said, “I will go closer to this strange thing. How can a bush continue burning without burning up?” When the LORD saw Moses was coming to look at the bush, God called to him from the bush, “Moses, Moses!” And Moses said, “Here I am.” Then God said, “Do not come any closer. Take off your sandals, because you are standing on holy ground.