וימתו הצפרדעים מן הבתים מן החצרת ומן השדת... ויסר הערב מפרעה מעבדיו ומעמו לא נשאר אחד
The frogs (most of them) died. The arov, wild beasts, and arbeh, locust, did not. Kli Yakar explains that Hashem sought to teach that one who gives himself up for Kiddush Hashem, to sanctify Hashem’s Name, will be saved. Thus, those frogs that climbed into the burning hot ovens belonging to the Egyptians – lived. The other frogs, who did not enter the ovens, but rather “chose” to invade the country, the fields, the homes – died. The ones that risked death for the glory of Hashem were spared; the others were not. It was this lesson that Chananyah, Mishael…