So Moses and Aaron went to Pharaoh and did just as the LORD had commanded. Aaron threw his staff down before Pharaoh and his officials, and it became a serpent.
10. And Moses and Aaron went in. Although they were now fully conscious of their vocation; and knew that they were endued with divine power for working miracles, yet would they never have dared to approach the fierce and cruel tyrant, unless the inward inspiration of the Spirit had armed them to persevere.
The first time that Moses made his application to Pharaoh, he produced his instructions only; now he is directed to produce his credentials, and does accordingly. 1. It is taken for granted that Pharaoh would challenge these demandants to work a miracle, that, by a performance evidently above the power of nature, they might prove their commission from the God of nature.
Commenting on Exodus 7:8-13
And Moses and Aaron went in unto Pharaoh,.... Into the palace of Pharaoh boldly, and with intrepidity, clothed with such power and authority, and assured of success: and they did as the Lord had commanded; they demanded in his name the dismission of the children of Israel, and upon his requiring a miracle to confirm their mission, wrought one as follows: and Aaron cast down...