21:2כ״א:ב׳
1 א

למועד אשר דבר אתו. דִּי מַלִּיל יָתֵהּ, אֶת הַמּוֹעֵד דִּבֵּר וְקָבַע כְּשֶׁאָמַר לוֹ לַמּוֹעֵד אָשׁוּב אֵלֶיךָ (שם י"ח), שָׂרַט לוֹ שְׂרִיטָה בַּכֹּתֶל, אָמַר לוֹ כְּשֶׁתַּגִּיעַ חַמָּה לִשְׂרִיטָה זוֹ בַּשָּׁנָה הָאַחֶרֶת, תֵּלֵד:

למועד אשר דבר אתו Render it as Onkelos translates: “At the appointed time which He had spoken: — the time He had said and appointed. When He had said to him (18:4) “At the set time I will return unto thee”, He scratched a mark in the wall and said to him (Genesis 53:6), “When the sunrays touch this mark next year she will bear a son” (Yalkut Shimoni on Torah 59:1).

2 ב

לזקניו. היה זיו איקונין שלו דומה לו:

In his old age. That his [Yitzchok’s] facial features were similar to his [Avraham’s].