Now Moses kept the flock of Jethro his father-in-law, the priest of Midian, and he led the flock to the far side of the desert and came to the mountain of God, to Horeb.
And He said, “Certainly I will be with you, and this will be a sign to you, that I have sent you: When you have brought forth the people out of Egypt, all of you shall serve God on this mountain.”