Midrash for Exodus 12:30

And Pharaoh rose up in the night (Exod. 12:30). Perhaps (he rose at) the third hour (9:00 a.m.), the time at which kings are accustomed to arise. (Therefore) Scripture says specifically in the night. Perhaps he was awakened by the princes and the princesses, (and therefore) the verse states he arose, to inform us that he went to the door of the servants’ quarters and aroused them. He went with them, calling out: “Where are Moses and Aaron resting?” as it is said: And he called for Moses and Aaron by night, and said: “Rise up, get you forth from among my people” (ibid., v. 31). Whereupon Moses replied: The Holy One, blessed be He, told us: And none of you shall go out of the door of his house until morning (ibid., v. 22). Are we thieves that we should steal away under the cover of night? No. We shall depart proudly, in full view of the Egyptians.

6. That God struck down all the firstborn of the Land of Egypt (Ex 12:29). [The text does not simply read] “the firstborn,” [but rather] “all the firstborn.” [The word “all” is meant to include both] the firstborn of man and the firstborn of woman, [that is,] the firstborn of [each] male and the firstborn of [each] female. This is how [it can be illustrated]: [In the case of] a single man who came to ten women and they gave birth to ten sons, each one would turn out to be a firstborn of a woman. [On the other hand, in the case of] ten men who all came to a [single] woman and they fathered ten sons, each one would turn out to be a firstborn of a man. You might imagine a house in which there was neither a firstborn of a man nor of a woman [and think, in such a case]“how could I fulfill the verse: for there was no house in which no one had died (Ex 12:30)?” Rabbi Abba bar Acha said: [in such a case,] the trustee of the household would die, as it is written, “ Shimri the chief – for though he was not the firstborn, yet his father made him chief. (I Ch 26:10)” A Tanna said in the name of R. Nathan: On the day that the firstborn of one of [the Egyptians] would die, [the Egyptian] would carve an icon of him and place it in the house. On that day, [the icon] was crushed, pulverized, and scattered, and it was as hard on the [Egyptian] as if he was burying his son again. R. Yudan said: Since the Egyptians would entomb [their dead] in their own houses, [on that day] the dogs went into the catacombs, pulled out the [bodies of] the firstborn from their tombs, and tore into them. It was as hard on [each Egyptian] as if he was burying his son again.

Another explanation: "And it was in the middle of the night" - this is [the meaning of] that which is written (Proverbs 31:18), "She has understanding as her merchandise is good, her candle does not, etc." You find that the verse stated (Exodus 12:30), "as there was not a house that did not have a dead person there." How? If you count each and every drop that an Egyptian put out to each and every woman [that had not yet given birth] or the first drop [to women that had already given birth from other men], it will be found that all of the boys were dying, as it is stated (Psalms 88:51), "And he smote every firstborn in Egypt, the beginning of their strength in the tents of Cham." The first drop [that were] female firstborns also died, except for Batya the daughter of Pharaoh who had a good (tov) defender; that was Moshe, as it is stated (Exodus 2:2), "and she saw that he was goodly (tov)." Hence Shlomo said "She has understanding as her merchandise is good." "And she gets up while it is still night" (Proverbs 31:15) - in what night? "And it was in the middle of the night."