For they cast down every man his rod, and they became serpents: but Aaron’s rod swallowed up their rods.
12. For they cast down every man. The number of the magicians is not expressed; and although Paul names two, Jannes and Jambres, C. has Mambres, the reading of the Vulgate. (2 Timothy 3:8,) it is probable that they were not the only ones, but the chief, and, as it were, the ringleaders. But I will not dispute this questionable point.
Pharaoh demands a miracle not to be convinced but hoping none will come, so he can cloak his unbelief. The rod becomes a serpent to strike terror into him, for God deals with sinners gradually, making them fear before they feel. Yet the magicians' imitation dulls the force of what should have broken his heart.
AI summary
Commenting on Exodus 7:8-13
For they cast down every man his rod, and they became serpents,.... That is, they seemed to be so, as Josephus (z) expresses it, but not really, in which he is followed by many; though some think that the devil assisted in this affair, and in an instant, as soon as the rods were cast down, removed them and put real serpents in their room...