יזוַיְנַגַּ֨ע יְהֹוָ֧ה | אֶת־פַּרְעֹ֛ה נְגָעִ֥ים גְּדֹלִ֖ים וְאֶת־בֵּית֑וֹ עַל־דְּבַ֥ר שָׂרַ֖י אֵ֥שֶׁת אַבְרָֽם
“And the L-RD plagued Pharaoh [with] great plagues as well as his household, because of the word of Sarai, Abram’s wife.”
al devar Sarai עַל־דְּבַ֥ר שָׂרַ֖י
From Midrash Tanchuma Lech Lecha 5
Furthermore, I will make an example of Pharaoh and his household, as it is said: And the L-RD plagued Pharaoh and his house with great plagues because of the word of Sarai (Gen. 12:17). What is indicated by the phrase Because of the word of Sarai? An angel descended with a staff from heaven at that moment, and when Pharaoh later approached her to remove her shoe, he struck him upon the hand, and when he approached to touch her clothing, the angel struck him again. However, the angel consulted Sarah before administering each blow. How do we know that? We know that because it is written: Because of the word of Sarai. Scripture does not say “Because of” or “For the sake of” or “On account of her merit,” but simply, Because of the word of Sarai. If Sarah told the angel to strike him, he struck him, and if she told him to desist, momentarily, he desisted. The officials, the officers, and all the members of his household were smitten by the angel simultaneously, as it is said: And the Lord plagued Pharaoh and his house with great plagues because of the word of Sarai. Every plague already known to man, and those yet to be experienced by mankind, descended upon him, his household, his many servants, the walls, the columns, the utensils, and all his possessions to fulfill the verse: There shall no mischief befall the righteous, but the wicked are filled with evil (Prov. 12:21).