Sarah the Punisher II

Pharaoh is punished for taking Sarai and the verse says he is punished על דבר שרי אשת אברהם (Bereishis 12:17). Artscroll renders it "because of Sarai," but Rashi quotes a fascinating Midrash that translates the phrase literally: "by the word of Sarai." Hashem sent an angel who did Sarai's bidding. When she said "strike," the angel attacked Pharaoh. (For an explanation of the unusual punishment chosen by Sarai, see this post.)

This Midrash begs the question. Why? Why didn't Hashem just stop Pharaoh directly? Why does He put it into Sarai's hands to mete out Pharaoh's punishment?

The answer can be found between the lines of a Midrash (B.R. 53:6, cited by the Ohr HaChaim to 12:13) which relates our episode to the parsha of Sotah, the suspected adulteress:

Rabbi Yitzchok said, "Hashem said 'If the woman did not adultery and is pure and innocent, she will have a child' (Bamidbar 5:28). This woman [Sarai] entered the house of Pharaoh and the house of Avimelech and left pure - certainly she should be blessed with a child! 

This is an extraordinary Midrash. It understands that a Sotah who turns out to be innocent is rewarded with a child not due to some mysterious power of Sotah water but simply because she withstood the test of being alone with a man. It certainly follows, says the Midrash, that Sarai, who withstood the advances of the King of Egypt, should be blessed with a child. Indeed she was and they named him Yitzchok.

(Not that this was a difficult test for our mother Sarai. She was a Tzadeikes and never entertained the thought, ח"ו. But she is rewarded nonetheless. Just because it's easy doesn't mean it doesn't count. On the contrary, if a test is easy for you, you should get extra credit!)

This explains why Hashem did not stop Pharaoh. To stop Pharaoh would undermine the test that ultimately created Yitzchok. Hashem put it in Sarai's hands. If she wants, she can drop Avraham and become the new Queen of Egypt. Or, if she so chooses, she has an angel at her disposal that will stop Pharaoh in his tracks. The decision is hers.