parshat Vayera: וְהוּא אַחֲרָיו

Sarah overhears the promise that she will have a son, and she laughs. Bereishit 18:10-11:

י וַיֹּאמֶר, שׁוֹב אָשׁוּב אֵלֶיךָ כָּעֵת חַיָּה, וְהִנֵּה-בֵן, לְשָׂרָה אִשְׁתֶּךָ; וְשָׂרָה שֹׁמַעַת פֶּתַח הָאֹהֶל, וְהוּא אַחֲרָיו.	10 And He said: 'I will certainly return unto thee when the season cometh round; and, lo, Sarah thy wife shall have a son.' And Sarah heard in the tent door, which was behind him.--
יא וְאַבְרָהָם וְשָׂרָה זְקֵנִים, בָּאִים בַּיָּמִים; חָדַל לִהְיוֹת לְשָׂרָה, אֹרַח כַּנָּשִׁים.	11 Now Abraham and Sarah were old, and well stricken in age; it had ceased to be with Sarah after the manner of women.--

What is meant by the phrase וְהוּא אַחֲרָיו? Rashi and Rashbam give the pshat answer - that it means that that the tent was behind the speaker. Even though we see הוּא and think person, here it refers to the tent -- or perhaps the tent door, while אַחֲרָיו refers to the speaker (one of the three who came in the guise of men).

However, Targum Yochanan and Targum Yerushalmi both give an alternative rendition - that it is Yishmael (וְהוּא) who stands behind the tent (אַחֲרָיו). This matches what you might imagine in the movie version - the camera pans away and we see Yishmael in the background, listening to all this, and hearing that a brother - competition - is to be born.

I would suggest a third, midrashic interpretation. Perhaps וְהוּא refers to the tent door at which Sarah stands, and אַחֲרָיו refers to the tent. Thus, this is not the front door of the tent. which Avraham sat by earlier, but a tent flap on the other side. Perhaps this is why they did not expect Sarah to overhear.

Indeed, in an earlier post, I put forth that the first pasuk of the parsha:

א וַיֵּרָא אֵלָיו ה, בְּאֵלֹנֵי מַמְרֵא; וְהוּא יֹשֵׁב פֶּתַח-הָאֹהֶל, כְּחֹם הַיּוֹם.

1 And the LORD appeared unto him by the terebinths of Mamre, as he sat in the tent door in the heat of the day;

was the source of the midrash that Avraham had a tent with four entrances. That is, כְּחֹם הַיּוֹם did not modify Avraham's action but rather the location פֶּתַח-הָאֹהֶל (=East). If a compass direction needs be specified for the door of his tent, presumably he has doors in other compass directions, and would do this to be hospitable, an idea which fits in with the general theme of Avraham's extreme hospitality. Here, in וְהוּא אַחֲרָיו, we might find another door, facing another compass direction.