Moses said not a word. In silent reverence before the Divine vision he covered his face, and when God disclosed the mission with which He charged him, of bringing the Israelites forth from the land of Egypt, he answered with humility, "Who am I, that I should go unto Pharaoh, and bring forth the children of Israel out of Egypt?" Thereupon spake God, "Moses, thou art meek, and I will reward thee for thy modesty. I will deliver the whole land of Egypt into thine hand, and, besides, I will let thee ascend unto the throne of My glory, and look upon all the angels of the heavens."
Moses Asked God Who Am I to Free Israel
Legends of the Jews 4:163