“He said: I will return to you at this time next year and, behold, a son for Sarah your wife. And Sarah was listening at the entrance of the tent, and it was behind him” (Genesis 18:10). “He said: I will return to you at this time next year…and it was behind him” – this is Ishmael. “And it was behind him” – because of seclusion.44Yishmael would stand at the entrance of the tent in order to ensure that men would not enter it when Sarah was alone, to avoid the seclusion of a man and a woman, which is forbidden.
“And it was behind him” – this refers to the angel, who looked behind him, sensing that light was coming from behind him.45Sarah’s body virtually glowed from her righteousness. “Abraham and Sarah were old, advanced in years; it had ceased to be with Sarah the manner of women” (Genesis 18:11). “Abraham and Sarah were old” – Rabbi Yoḥanan said: It was already stated: “Abraham and Sarah were old,” why does the verse state [again]: “Abraham was old”? (Genesis 24:1).46That verse is referring to a time forty years later than our verse.
The explanation is that the Holy One blessed be He restored him to the days of his youth;47When the angels came to him he became reinvigorated. Consequently, he had to go through the ageing process again. therefore, it was necessary to write a second time: Abraham was old. Rabbi Ami said: Here it refers to old age with vitality, and there it refers to old age without vitality. “It had ceased [ḥadal] to be with Sarah the manner of women” – just as it says: “If you refrain [teḥdal] from vowing” (Deuteronomy 23:23), [meaning that] it had ceased, just as it says: “And he refrained [veḥadal] from offering the Paschal lamb” (Numbers 9:13).