Why did Hashem remove the wild animals, rather than killing them off (like He killed the frogs)?
Rashi and Ramban: Because then the Egyptians would have derived benefit from the animals' skins. 1
Oznayim la'Torah: Because, as opposed to the frogs which were created specifically for the plague of Tzefarde'a, and which were therefore superfluous, Hashem had gathered the wild animals to Egypt from all over the world. Now that they had performed their task, He sent them back to where they came from.
Ramban (citing the Midrash): And it was Hashem's intention that the plagues should cause the Egyptians to suffer, and not that they should benefit from them in any way.
QUESTIONS ON RASHI
Rashi writes: "'He removed (va'Yasar) the Arov' - They did not [merely] die, as the frogs had...." But the term "v'Sar he'Arov" already appeared above (8:25); why didn't Rashi point this out earlier?
Gur Aryeh: In verse 8:25, Moshe was responding to Pharaoh, informing him that yes, the plague would be removed. It was not crucial to specify by what means. Our verse tells us what Hashem did; it has to specify what happened (not just the result - that the Makah ended). If the verse says "they were removed," rather than "they died," we need to explain why.
