Bereshit (Genesis) Chapter 21

9And Sarah saw the son of Hagar the Egyptian, whom she had borne to Abraham, making merry.   טוַתֵּ֨רֶא שָׂרָ֜ה אֶת־בֶּן־הָגָ֧ר הַמִּצְרִ֛ית אֲשֶׁר־יָֽלְדָ֥ה לְאַבְרָהָ֖ם מְצַחֵֽק:
making merry. Heb. מְצַחֵק. An expression of idolatry, as it is said (Exod. 32:6): “and they rose up to make merry” (לְצַחֵק) . Another explanation: An expression of illicit sexual relations, as it is said (below 39:17): “to mock (לְצַחֶק) me.” Another explanation: An expression of murder, as it is said (II Sam. 2:14): “Let the boys get up now and sport (וַיִשַׂחֲקוּ) before us, etc.” - [from Gen. Rabbah 53:11]   מְצַחֵֽק.  לְשׁוֹן עֲבוֹדָה זָרָה, כְּמוֹ שֶׁנֶּאֱמַר וַיָּקֻמוּ לְצַחֵק (שמות ל"ב), דָּבָר אַחֵר לְשׁוֹן גִּלּוּי עֲרָיוֹת, כְּמָה דְּתֵימָא לְצַחֶק בִּי (בראשית ל"ט), דָּבָר אַחֵר לְשׁוֹן רְצִיחָה, כְּמוֹ יָקוּמוּ נָא הַנְּעָרִים וִישַׂחֲקוּ לְפָנֵינוּ וְגוֹ' (שמואל ב ב'):
10And Sarah said to Abraham, "Drive out this handmaid and her son, for the son of this handmaid shall not inherit with my son, with Isaac."   יוַתֹּ֨אמֶר֙ לְאַבְרָהָ֔ם גָּרֵ֛שׁ הָֽאָמָ֥ה הַזֹּ֖את וְאֶת־בְּנָ֑הּ כִּ֣י לֹ֤א יִירַשׁ֙ בֶּן־הָֽאָמָ֣ה הַזֹּ֔את עִם־בְּנִ֖י עִם־יִצְחָֽק:
with my son, etc.. From Sarah’s reply, “For the son of this handmaid shall not inherit with my son,” you learn that he would quarrel with Isaac regarding the inheritance and say,“ I am the firstborn and should take two portions,” and they would go out to the field, and he would take his bow and shoot arrows at him, as it is said (Prov. 26:18f.): “Like one who wearies himself shooting firebrands, etc. and says: Am I not joking?” - [from above source]   עִם־בְּנִי וגו'.  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):
with my son, with Isaac. (Gen. Rabbah 53:11) Just because he is my son, even if he were not as deserving as Isaac, or [if he were] as deserving as Isaac, even if he were not my son, this one [Ishmael] does not deserve to inherit with him. How much more so [does he not deserve to inherit] with my son, with Isaac, who has both qualities!-   עִם־בְּנִי עִם־יִצְחָֽק.  מִכֵּיוָן שֶׁהוּא בְנִי אֲפִלּוּ אִם אֵינוֹ הָגוּן כְּיִצְחָק, אוֹ הָגוּן כְּיִצְחָק אֲפִלּוּ אֵינוֹ בְנִי, אֵין זֶה כְדַאי לִירַשׁ עִמּוֹ, קַל וָחֹמֶר עִם בְּנִי עִם יִצְחָק, שֶׁשְּׁתֵיהֶן בּוֹ (בראשית רבה):
11But the matter greatly displeased Abraham, concerning his son.   יאוַיֵּ֧רַע הַדָּבָ֛ר מְאֹ֖ד בְּעֵינֵ֣י אַבְרָהָ֑ם עַ֖ל אוֹדֹ֥ת בְּנֽוֹ:
concerning his son. Because he heard that he had fallen to wicked ways (Tan. Shemoth 1). According to its simple meaning, however, [it means] because she told him to send him away.   עַל אודות בְּנֽוֹ.  שֶׁשָּׁמַע שֶׁיָּצָא לְתַרְבּוּת רָעָה (בראשית רבה), וּפְשׁוּטוֹ עַל שֶׁאָמְרָה לוֹ לְשַׁלְּחוֹ:
12And God said to Abraham, "Be not displeased concerning the lad and concerning your handmaid; whatever Sarah tells you, hearken to her voice, for in Isaac will be called your seed.   יבוַיֹּ֨אמֶר אֱלֹהִ֜ים אֶל־אַבְרָהָ֗ם אַל־יֵרַ֤ע בְּעֵינֶ֨יךָ֙ עַל־הַנַּ֣עַר וְעַל־אֲמָתֶ֔ךָ כֹּל֩ אֲשֶׁ֨ר תֹּאמַ֥ר אֵלֶ֛יךָ שָׂרָ֖ה שְׁמַ֣ע בְּקֹלָ֑הּ כִּ֣י בְיִצְחָ֔ק יִקָּרֵ֥א לְךָ֖ זָֽרַע:
hearken to her voice. (to the voice of the holy spirit within her.) We learn from here that Abraham was inferior to Sarah in prophecy. — [from Exod. Rabbah 1:1, Tan. Shemoth 1]   שְׁמַע בקולה.  (בקול רוח הקודש שבה.) לָמַדְנוּ שֶׁהָיָה אַבְרָהָם טָפֵל לְשָׂרָה בִּנְבִיאוּת: