Exodus 3:10-12

and now, come, and I send thee unto Pharaoh, and bring thou out My people, the sons of Israel, out of Egypt.'

And Moses saith unto God, `Who am I, that I go unto Pharaoh, and that I bring out the sons of Israel from Egypt?'

and He saith, `Because I am with thee, and this is to thee the sign that I have sent thee: in thy bringing out the people from Egypt--ye do serve God on this mount.'