Moses was keeping the flock of his father-in-law Jethro, the priest of Midian, and led the sheep beyond the wilderness to Horeb, the mountain of God. There the angel of the Lord appeared to him in a flame of fire from the middle of a bush. The bush was burning but was not consumed, and Moses turned aside to look. God called him by name, told him not to come closer and to take off his sandals, because the place was holy ground. He identified himself as the God of Moses' father, the God of Abraham, Isaac and Jacob, and Moses hid his face in fear.
The Lord said he had seen the affliction of his people, had heard their cry because of their taskmasters and knew their sufferings. He had come down to deliver them from the Egyptians and bring them to a good and broad land flowing with milk and honey, now home to several peoples. He then sent Moses to Pharaoh to bring the Israelites out of Egypt.
Moses asked who he was to go to Pharaoh. God answered that he would be with him, and that the sign would be that, after bringing the people out, they would worship God on that same mountain. Moses asked what to say if they asked God's name, and God replied I AM WHO I AM, telling him to say to Israel that I AM had sent him. God added that he is the Lord, the God of their fathers, and that this is his name forever.
God gave instructions: gather the elders of Israel, tell them the Lord had seen what was done to them, and ask Pharaoh for permission to go a three-day journey into the wilderness to sacrifice. He foretold that the king would not let them go unless forced by a mighty hand, but that he would work wonders in Egypt. When they left, the people would not go empty-handed: the women would ask their Egyptian neighbors for silver, gold and clothing.