by Rabbi Avi Billet
In the prelude to the 10th plague, the verse says (11:5) וּמֵ֣ת כָּל־בְּכוֹר֘ בְּאֶ֣רֶץ מִצְרַיִם֒ מִבְּכ֤וֹר פַּרְעֹה֙ הַיֹּשֵׁ֣ב עַל־כִּסְא֔וֹ עַ֚ד בְּכ֣וֹר הַשִּׁפְחָ֔ה אֲשֶׁ֖ר אַחַ֣ר הָרֵחָ֑יִם וְכֹ֖ל בְּכ֥וֹר בְּהֵמָֽה: In the actual plague it says (12:30) - וַיְהִ֣י׀ בַּחֲצִ֣י הַלַּ֗יְלָה וַֽיקֹוָק֘ הִכָּ֣ה כָל־בְּכוֹר֘ בְּאֶ֣רֶץ מִצְרַיִם֒ מִבְּכֹ֤ר פַּרְעֹה֙ הַיֹּשֵׁ֣ב עַל־כִּסְא֔וֹ עַ֚ד בְּכ֣וֹר הַשְּׁבִ֔י אֲשֶׁ֖ר בְּבֵ֣ית הַבּ֑וֹר וְכֹ֖ל בְּכ֥וֹר בְּהֵמָֽה: Both describe that the death toll encompasses the first borns, from the first born of Pharaoh to the lowest status Egyptian (though it changes from the warning to the actuality as noted in bold above– which will be addressed below), and the first born animals. The verses which follow each of the above verses talk about how there will be, and indeed there was, a terribly huge cry in all of Egypt, with the verse in chapter 12:31 concluding with our title – no house was spared.
How could that be? If a first born for the purpose of this plague is a male, not every household’s firstborn is a son. The father might not be a firstborn. And if he has only daughters, then how could his house NOT be spared? [Rashi and Ibn Ezra say that the Pasuk is generalizing, and that since it was a majority of houses, that is what the Pasuk refers to, even though it says no house was spared…]