The magicians did so. — It cannot be concluded from this that the magicians had the power of creating frogs. All that the writer means to express is, that they seemed to Pharaoh and to the Court to do on a small scale what Moses and Aaron had done on the largest possible scale. The means which they employed was probably sleight-of-hand. It has been well observed that they would have shown their own power and the power of their gods far more satisfactorily had they succeeded in taking the frogs away.
Related Commentaries of Exodus 8:7
Exodus 8:7
7 And the magicians did so with their enchantments, and brought up frogs upon the land of Egypt.