The account of the preparation of Moses to be deliverer starts in Exodus 3. It begins with God confronting him at the burning bush. Moses needs to be impressed by the fact that this is a very holy call at a very holy moment in a very holy place. God is aware of the suffering of His people and He is ready to deliver them. He wants Moses to be his representative before Pharaoh and before His people to make this deliverance happen.
Chapter 3 can outlined as follows:
When Moses was shepherding Jethro’s flock around Mount Horeb, God appears to him in the form of a bush that is burning but is not consumed.
God tells Moses that He is aware of the plight of the Israelites and tells Moses that He is sending him to Pharaoh.
Moses is not convinced that he is the right person for the job of delivering the Israelites. In fact, he responds to the LORD with five objections (3:11 – 4:17). The LORD constantly and repeatedly assures Moses that He will equip him for the job and promises His constant presence.
In his first objection, Moses asks “Who am I?” His second objection asks God, “Who are you?” Moses wants to be prepared if (and when) confronted by the Israelites concerning where he gets the authority to tell them what to do.
Whereas the first answer involves who God is, the second answer contains a description of what He does.