Genesis Chapter 17

24And Abraham was ninety-nine years old, when he was circumcised of the flesh of his foreskin.   כדוְאַ֨בְרָהָ֔ם בֶּן־תִּשְׁעִ֥ים וָתֵ֖שַׁע שָׁנָ֑ה בְּהִמֹּל֖וֹ בְּשַׂ֥ר עָרְלָתֽוֹ:
when he was circumcised: Heb. בְּהִמֹּלוֹ, when it was done to him, like (above 2:4): “when they were created (בְּהִבָּרְאָם).”   בהמולו: בהפעלו, כמו (ב ד) בהבראם:
25And Ishmael his son was thirteen years old, when he was circumcised of the flesh of his foreskin.   כהוְיִשְׁמָעֵ֣אל בְּנ֔וֹ בֶּן־שְׁל֥שׁ עֶשְׂרֵ֖ה שָׁנָ֑ה בְּהִ֨מֹּל֔וֹ אֵ֖ת בְּשַׂ֥ר עָרְלָתֽוֹ:
when he was circumcised of the flesh of his foreskin: Concerning Abraham, it does not say אֵת, because he was lacking only the severing of the flesh, because it had already been flattened out by intercourse, but Ishmael, who was a youth, required that the foreskin be severed and the corona be uncovered. Therefore, in his case, it is אֵת. Gen. Rabbah (47:8).   בהמולו את בשר ערלתו: באברהם לא נאמר את, לפי שלא היה חסר אלא חתוך בשר, שכבר נתמעך על ידי תשמיש, אבל ישמעאל שהיה ילד הוזקק לחתוך ערלה ולפרוע המילה, לכך נאמר בו את:
26On that very day, Abraham was circumcised, and [so was] Ishmael his son.   כובְּעֶ֨צֶם֙ הַיּ֣וֹם הַזֶּ֔ה נִמּ֖וֹל אַבְרָהָ֑ם וְיִשְׁמָעֵ֖אל בְּנֽוֹ:
On that very day: when Abraham reached the age of ninety-nine and Ishmael [reached the age of] thirteen,“Abraham was circumcised, and [so was] Ishmael his son.”   בעצם היום הזה: שמלאו לאברהם תשעים ותשע שנה ולישמעאל שלש עשרה שנים נמול אברהם וישמעאל בנו:
27And all the people of his household, those born in his house and those bought with money from foreigners, were circumcised with him.   כזוְכָל־אַנְשֵׁ֤י בֵיתוֹ֙ יְלִ֣יד בָּ֔יִת וּמִקְנַת־כֶּ֖סֶף מֵאֵ֣ת בֶּן־נֵכָ֑ר נִמֹּ֖לוּ אִתּֽוֹ: