Exodus 3:1-2, 12

Moses was shepherding the flock of Jethro, his father-in-law, the priest of Midian. He led the flock to the west end of the wilderness and came to the mountain of God, Horeb. The angel of GOD appeared to him in flames of fire blazing out of the middle of a bush. He looked. The bush was blazing away but it didn’t burn up.

“I’ll be with you,” God said. “And this will be the proof that I am the one who sent you: When you have brought my people out of Egypt, you will worship God right here at this very mountain.”