3 But I will harden Pharaoh's heart, and though I multiply my signs and wonders in the land of Egypt, 4 Pharaoh will not listen to you. Then I will lay my hand on Egypt and bring my hosts, my people the children of Israel, out of the land of Egypt by great acts of judgment. 5 The Egyptians shall know that I am the Lord, when I stretch out my hand against Egypt and bring out the people of Israel from among them." 6 Moses and Aaron did so; they did just as the Lord commanded them. 7 Now Moses was eighty years old, and Aaron eighty-three years old, when they spoke to Pharaoh.
8 Then the Lord said to Moses and Aaron, 9 "When Pharaoh says to you, 'Prove yourselves by working a miracle,' then you shall say to Aaron, 'Take your staff and cast it down before Pharaoh, that it may become a serpent.'" 10 So Moses and Aaron went to Pharaoh and did just as the Lord commanded. Aaron cast down his staff before Pharaoh and his servants, and it became a serpent. 11 Then Pharaoh summoned the wise men and the sorcerers, and they, the magicians of Egypt, also did the same by their secret arts. 12 For each man cast down his staff, and they became serpents. But Aaron's staff swallowed up their staffs.
Matthew Henry's Commentary on Exodus 7:3-12
Commentary on Exodus 7:1-7
(Read Exodus 7:1-7)
God glorifies himself. He makes people know that he is Jehovah. Israel is made to know it by the performance of his promises to them, and the Egyptians by the pouring out of his wrath upon them. Moses, as the ambassador of Jehovah, speaking in his name, laid commands upon Pharaoh, denounced threatenings against him, and called for judgments upon him. Pharaoh, proud and great as he was, could not resist. Moses stood not in awe of Pharaoh, but made him tremble. This seems to be meant in the words, Thou shalt be a god unto Pharaoh. At length Moses is delivered from his fears. He makes no more objections, but, being strengthened in faith, goes about his work with courage, and proceeds in it with perseverance.
Commentary on Exodus 7:8-13
(Read Exodus 7:8-13)
What men dislike, because it opposes their pride and lusts, they will not be convinced of; but it is easy to cause them to believe things they wish to be true. God always sends with his word full proofs of its Divine authority; but when men are bent to disobey, and willing to object, he often permits a snare to be laid wherein they are entangled. The magicians were cheats, trying to copy the real miracles of Moses by secret sleights or jugglings, which to a small extent they succeeded in doing, so as to deceive the bystanders, but they were at length obliged to confess they could not any longer imitate the effects of Divine power. None assist more in the destruction of sinners, than such as resist the truth by amusing men with a counterfeit resemblance of it. Satan is most to be dreaded when transformed into an angel of light.