For the first forty years of his life, Moses lived in a place of strength. As a member of Pharaoh's household he had social prestige, wealth (Hebrews 11:26), and youthful strength. When he became aware of and troubled by his peoples' oppression he used this strength to exact vigilante justice on an oppressive Egyptian. That wasn't God’s plan for deliverance. He had to flee for his life and ended up tending livestock in the quiet fields of Midian for his second forty years.
So he passed his youth in a palace of power and his middle age in pastures of peaceful obscurity. Then one day he stumbled on a burning bush, which turned out to be God's surprising call for his third forty years:
Behold, the cry of the people of Israel has come to me, and I have also seen the oppression with which the Egyptians oppress them. Come, I will send you to Pharaoh that you may bring my people, the children of Israel, out of Egypt. (Exodus 3:9-10)
This call scared Moses out of his wits. So much so that he argued his case face-to-face with God.
Objection 1: I'm a nobody, God.
"Who am I that I should go to Pharaoh and bring the children of Israel out of Egypt?" (Exodus 3:11). Any fame or social credibility I may have once had is gone. In fact, I'm a shepherd and "every shepherd is an abomination to the Egyptians" (Genesis 46:34).
Objection Overruled: "I will be with you” (Exodus 3:12). This calling is not based on your credibility but on Mine. I don't want Egypt or Israel impressed with you. I want them impressed with Me.
[Read the rest of the article at Desiring God.]