Chumashחומש

מצחק. לְשׁוֹן עֲ"זָ, כְּמוֹ שֶׁנֶּאֱמַר וַיָּקֻמוּ לְצַחֵק (שמות ל"ב), דָּ"אַ לְשׁוֹן גִּלּוּי עֲרָיוֹת, כְּמָה דְּתֵימָא לְצַחֶק בִּי (בראשית ל"ט), דָּ"אַ לְשׁוֹן רְצִיחָה, כְּמוֹ יָקוּמוּ נָא הַנְּעָרִים וִישַׂחֲקוּ לְפָנֵינוּ וְגוֹ' (שמואל ב ב'), שֶׁהָיָה מֵרִיב עִם יִצְחָק עַל הַיְרֻשָּׁה וְאוֹמֵר אֲנִי בְּכוֹר וְנוֹטֵל פִּי שְׁנַיִם, וְיוֹצְאִים בַּשָּׂדֶה וְנוֹטֵל קַשְׁתּוֹ וְיוֹרֶה בוֹ חִצִּים, כְּמָה דְּתֵימָא כְּמִתְלַהְלֵהַּ הַיֹּרֶה זִקִּים וְגוֹ' וְאָמַר הֲלֹא מְשַׂחֵק אָנִי (משלי כ"ו):

מצחק MAKING SPORT — This means worshipping idols, as it is said in reference of the Golden Calf, (Exodus 32:6) “And they rose up to make merry (לצחק).” Another explanation is that it refers to immoral conduct, just as you say in reference to Potiphar’s wife, (Genesis 39:17) “To mock (לצחק) at me.” Another explanation is that it refers to murder, as (2 Samuel 2:14) “Let the young men, I pray thee, arise and make sport (וישחקו) before us” (where they fought with and killed one another) From Sarah’s reply — “for the son of this bondwoman shall not be heir with my son״ — you may infer that he (Ishmael) was quarrelling with Isaac about the inheritance, saying, “I am the first-born and will, therefore, take a double portion”. They went into the field and he (Ishmael) took his bow and shot arrows at him (Isaac), just as you say (Proverbs 26:18-19) “As a madman who casteth firebrands, [arrows and death] and says: I am only מצחק mocking” (Genesis Rabbah 53:11).

עם בני עם יצחק. מִכֵּיוָן שֶׁהוּא בְנִי אֲפִלּוּ אִם אֵינוֹ הָגוּן כְּיִצְחָק, אוֹ הָגוּן כְּיִצְחָק אֲפִלּוּ אֵינוֹ בְנִי, אֵין זֶה כְדַאי לִירַשׁ עִמּוֹ, קַ"וָ עִם בְּנִי עִם יִצְחָק, שֶׁשְּׁתֵיהֶן בּוֹ (בראשית רבה):

עם בני עם יצחק WITH MY SON, WITH ISAAC —For since this is my son, even though he were not as good as Isaac really is, or if he were as good a man as Isaac really is, even though he were not my son, this one (Ishmael) is not deserving of inheriting with him: how much less is he deserving of inheriting with my son, with Isaac — with one who possesses both these qualities (of being my son and of being the good man Isaac) (Genesis Rabbah 53:11).

על אודות בנו. שֶׁשָּׁמַע שֶׁיָּצָא לְתַרְבּוּת רָעָה (בראשית רבה), וּפְשׁוּטוֹ עַל שֶׁאָמְרָה לוֹ לְשַׁלְּחוֹ:

על אדות בנו ON ACCOUNT OF HIS SON — because he heard that he had taken to degenerate ways (Exodus Rabbah 1:1). The real meaning, however, is because she (Sarah) had told him to send him away.

שמע בקולה. לָמַדְנוּ שֶׁהָיָה אַבְרָהָם טָפֵל לְשָׂרָה בִּנְבִיאוּת:

שמע בקולה HEARKEN UNTO HER VOICE — we may infer that Abraham was inferior to Sarah in respect of prophecy (Exodus Rabbah 1:1).