וה׳ פקד את שרה כל מקום שנאמר וה׳ הוא ובית דינו. ישב עליו בדין, כתיב אם לא נטמאה וגו׳ וטהורה היא ונקתה זרע וגם יולדת זכר, ושרה נסתרה ולא נטמאה. ואין להקשות מן וה׳ שמים עשה שהרי כן פירושו הוא הבעל רחמים עם מדת דינו שמים עשה. כמו שפירשתי גבי ביום עשות ה׳ א׳ ארץ ושמים. וה' פקד את שרה, “and after Hashem had taken due note of Sarah, etc;” whenever in the Torah the name of Hashem is introduced with the prefix ו, meaning “and,” it is a hint that G-d did not act singlehandedly but in consonance with His heavenly Tribunal. (Compare B’reshit Rabbah 51,2) In B’reshit Rabbah 53,6 this function of the Heavenly Tribunal is dealt with at greater length, especially in connection with Numbers 5,28 where the subject is the woman whose husband accused her of violating a specific command not to be alone with a certain man. This woman denied that she had committed an indiscretion, and the Torah promises that if she told the truth, and drank from the “bitter” waters, she will be rewarded with bearing a child she had been unable to conceive prior to this scandal. It is foolish to raise the question that since we know that G-d had known the truth all along, just as He does all the time, why was a miracle needed to demonstrate this truth? Her husband had not known, nor had her peers.
את שרה לרבות כל העקרות. את שרה, the word את here seems superfluous, as we do not hear about other barren women suddenly becoming pregnant at the same time. As a result of Avraham having prayed for the women in Avimelech’s palace to be able to give birth, even though his own wife had been unable to do so, he was rewarded in that she now became pregnant. All other barren women at the time were also now able to conceive. (Compare Torah Shleymah, 11, on this verse).
כאשר אמר שוב אשוב. כאשר אמר, “as He had said,” when the angel said that he would return around the same time in the following year and by then Sarah would have a baby. (Genesis 18,10)
כאשר דבר ביום ההוא כרת ה׳ ברית את אברהם וגו'. כאשר דבר, “as He had spoken.” A reference to a previous prophecy in Genesis 15,18, when G-d had concluded His first covenant with Avraham.