"And these are the generations of Isaac son of Abraham" (Genesis 25:19). It is written, "The father of a righteous one will greatly rejoice, and he who begets a wise son will be glad in him" (Proverbs 23:24). There is rejoicing when one is a righteous son of a righteous father. "And it came to pass in the days of Ahaz" and so on. The ministering angels said before the Holy One, blessed be He: Master of the universe, woe that Ahaz reigns! He said to them: He is the son of Yotam, and his father was righteous; I cannot stretch out My hand against him. "And he who begets a wise son will be glad in him." From where do you say that anyone who has a son who toils in Torah is filled with compassion for him? Scripture teaches, "and he who begets a wise son will be glad in him." I know this only of a father who is flesh and blood; from where that even the Holy One, blessed be He, is filled with compassion for him? Scripture teaches, "My son, if your heart is wise, my own heart will be glad" (Proverbs 23:15). "The crown of the elders is grandchildren" (Proverbs 17:6). The fathers are a crown to the children and the children a crown to the fathers. The fathers are a crown to the children, as it is said, "and the glory of children is their fathers." And the children are a crown to the fathers, as it is said, "the crown of the elders is grandchildren." They said: Abraham was saved from the fiery furnace only by the merit of Jacob our father. This is like one who had a case before the ruler, and his sentence came out from before the ruler to be burned, but that ruler foresaw by his astrology that he was destined to beget a daughter who would marry the king. He said: He is worthy to be saved by the merit of his daughter. So too the sentence of Abraham our father came out to be burned before Nimrod; the Holy One, blessed be He, foresaw that Jacob was destined to come from him, and said: He is worthy to be saved by the merit of Jacob. This is what is written, "Therefore thus says the LORD to the house of Jacob, who redeemed Abraham" (Isaiah 29:22). Abram is called Abraham, as it is said, "Abram, he is Abraham" (I Chronicles 1:27). Isaac is called Abraham, as it is written, "And these are the generations of Isaac son of Abraham; Abraham." Jacob is called Israel, as it is written, "Your name shall no longer be called Jacob, but Israel" (Genesis 35:10). Isaac is called Israel, as it is written, "And these are the names of the children of Israel who came into Egypt, Jacob" (Genesis 46:8). Abraham is called Israel - this is a deep matter - "And the sojourning of the children of Israel who dwelt in Egypt and in the land of Canaan and in the land of Goshen was four hundred and thirty years" (Exodus 12:40). Isaac resembled Abraham (as written in the verse, "who would have said to Abraham").
A Righteous Son and Father Each Spared for the Others Sake
Yalkut Shimoni on Torah 110:10
פרשת תולדות(בראשית כה יט) וְאֵלֶּה תּוֹלְדֹת יִצְחָק בֶּן אַבְרָהָם, כְּתִיב (משלי כג, כד) "גִּיל יָגִיל אֲבִי צַדִּיק וְיוֹלֵד חָכָם יִשְׂמַח בּוֹ". גִּילָה בִּזְמַן שֶׁהוּא צַדִּיק בֶּן צַדִּיק "וַיְהִי בִּימֵי אָחָז" וְגוֹ', אָמְרוּ מַלְאֲכֵי הַשָּׁרֵת לִפְנֵי הַקָּדוֹשׁ בָּרוּךְ הוּא רִבּוֹנוֹ שֶׁל עוֹלָם וַוי שֶׁמָּלַךְ אָחָז, אָמַר לָהֶם בֶּן יוֹתָם הוּא, וְאָבִיו צַדִּיק הָיָה, אֵינִי יָכוֹל לִפְשׁוֹט יָדִי בּוֹ. "וְיוֹלֵד חָכָם יִשְׂמַח בּוֹ", מִנַּיִן אַתָּה אוֹמֵר כָּל מִי שֶׁיֵּשׁ לוֹ בֵּן יָגֵעַ בַּתּוֹרָה שֶׁהוּא מִתְמַלֵּא עָלָיו רַחֲמִים תַּלְמוּד לוֹמַר "וְיּוֹלֵד חָכָם יִשְׂמַח בּוֹ". אֵין לִי אֶלָּא אָבִיו בָּשָׂר וָדָם, מִנָלָן שֶׁאֲפִילוּ הַקָּדוֹשׁ בָּרוּךְ הוּא מִתְמַלֵּא עָלָיו רַחֲמִים, תַּלְמוּד לוֹמַר (משלי כג, טו) "בְּנִי אִם חָכָם לִבֶּךָ יִשְׂמַח לִבִּי גַם אָנִי". עֲטֶרֶת זְקֵנִים בְּנֵי בָנִים, הָאָבוֹת עֲטָרָה לַבָּנִים וְהַבָּנִים עֲטָּרָה לָאָבוֹת הָאָבוֹת עֲטָרָה לַבָּנִים, שֶׁנֶּאֱמַר (שם) "וְתִפְאֶרֶת בָּנִים אֲבוֹתָם" וְהַבָּנִים עֲטָרָה לָאָבוֹת שֶׁנֶּאֱמַר (שם) "עֲטֶרֶת זְקֵנִים בְּנֵי בָנִים" אָמְרוּ לֹא נִצּוֹל אַבְרָהָם מִכִּבְשַׁן הָאֵשׁ אֶלָּא בִּזְכוּת יַעֲקֹב אָבִינוּ מָשָׁל לְאֶחָד שֶׁהָיָה לוֹ דִּין לִפְנֵי הַשִּׁלְטוֹן, וְיָצָא דִּינוֹ מִלִּפְנֵי הַשִּׁלְטוֹן לִשָּׂרֵף, וְצָפָה אוֹתוֹ שִׁלְטוֹן בְּאִיסְטְרוֹלוֹגוּת שֶׁלּוֹ, שֶׁהוּא עָתִיד לְהוֹלִיד בַּת וְהִיא נִשֵּׂאת לַמֶּלֶךְ, אָמַר כְּדַאי הוּא לְהִנָּצֵל בִּזְכוּת בִּתּוֹ, כָּךְ יָצָא דִּינוֹ שֶׁל אַבְרָהָם אָבִינוּ לִשָּׂרֵף לִפְנֵי נִמְרוֹד, צָפָה הַקָּדוֹשׁ בָּרוּךְ הוּא שֶׁעָתִיד יַעֲקֹב לָצֵאת מִמֶּנּוּ, אָמַר הַקָּדוֹשׁ בָּרוּךְ הוּא כְּדַאי הוּא לְהִנָּצֵל בִּזְכוּתוֹ שֶׁל יַעֲקֹב. הֲדָא הוּא דִכְתִיב "לָכֵן כֹּה אָמַר ה' אֶל בֵּית יַעֲקֹב אֲשֶׁר פָּדָה אֶת אַבְרָהָם". אַבְרָם נִקְרָא אַבְרָהָם, שֶׁנֶּאֱמַר (דברי הימים א' א, כז) "אַבְרָם הוּא אַבְרָהָם". יִצְחָק נִקְרָא אַבְרָהָם, דִּכְתִיב וְאֵלֶּה תּוֹלְדֹת יִצְחָק בֶּן אַבְרָהָם אַבְרָהָם. יַעֲקֹב נִקְרָא יִשְׂרָאֵל, דִּכְתִיב (בראשית לה, י) "לֹא יִקָּרֵא שִׁמְךָ עוֹד יַעֲקֹב כִּי אִם יִשְׂרָאֵל". יִצְחָק נִקְרָא יִשְׂרָאֵל, דִּכְתִיב (בראשית מו, ח) "וְאֵלֶּה שְׁמוֹת בְּנֵי יִשְׂרָאֵל הַבָּאִים מִצְרַיְמָה יַעֲקֹב" אַבְרָהָם נִקְרָא יִשְׂרָאֵל, מִלְתָא עֲמִיקְתָּא הִיא דֵּין "וּמוֹשַׁב בְּנֵי יִשְׂרָאֵל אֲשֶׁר יָשְׁבוּ בְּמִצְרַיִם (וּבְאֶרֶץ כְּנַעַן וּבְאֶרֶץ גּשֶׁן) שְׁלוֹשִׁים שָׁנָה וְאַרְבַּע מֵאוֹת שָׁנָה". יִצְחָק דּוֹמֶה לְאַבְרָהָם (כָּתוּב בַּפָּסוּק מִי מִלֵּל לְאַבְרָהָם).