"And also that nation whom they shall serve" (Genesis 15:14). The word "also" comes to include the four kingdoms. "Will I judge" (in Hebrew, the verb is written with two letters, dan anokhi): with these two letters the Holy One, blessed be He, assured Abraham our father that He would redeem his children, and that if they repented He would redeem them by seventy-two letters. For Rav Yudan said: from "to take Him a nation" until "and by great terrors" (Deuteronomy 4:34) you find seventy-two letters. And if a person says to you they are seventy-five, say to him: subtract the second "nation," which does not count in the reckoning. Rav Avin said: He redeems them by His Name, for the Name of the Holy One, blessed be He, is seventy-two letters. "And afterward they shall come out with great substance" (Genesis 15:14). It is not written here "after," but "afterward" [meaning: only after a sequence] -- after I bring upon them ten plagues, afterward they shall go out. Abraham said to Him: "Am I too in the bondage?" He said to him: "And you shall go to your fathers in peace; you shall be buried in a good old age" (Genesis 15:15). Resh Lakish said: There are three of whom "a good old age" is written -- Abraham and David, and Gideon was equal to them yet was not equal to them. Why? Because "Gideon made it into an ephod" (Judges 8:27), turning it into idolatry.
The Two Letters and the Seventy-Two-Letter Name of Redemption
Yalkut Shimoni on Torah 77:11
(בראשית טו יד-טו) וְגַם אֶת הַגּוֹי אֲשֶׁר יַעֲבוֹדוּ. גַּם לְרַבּוֹת אַרְבַּע מַלְכֻיּוֹת דָּן אָנֹכִי, בִּשְׁתֵי אוֹתִיּוֹת הַלָּלוּ הִבְטִיחַ הַקָּדוֹשׁ בָּרוּךְ הוּא אֶת אַבְרָהָם אָבִינוּ שֶׁהוּא גּוֹאֵל אֶת בָּנָיו, וְשֶׁאִם יַעֲשׂוּ תְּשׁוּבָה גּוֹאֲלָן בְּשִׁבְעִים וּשְׁתַּיִם אוֹתִיּוֹת. דְּאָמַר רַב יוּדָן, (דברים ד, לד) מִ"לָבוֹא לָקַחַת לוֹ גּוֹי" עַד "וּבְמוֹרָאִים גְּדוֹלִים" אַתְּ מוֹצֵא שִׁבְעִים וּשְׁתַּיִם אוֹתִיּוֹת וְאִם יֹאמַר לְךָ אָדָם שִׁבְעִים וְחָמֵשׁ הֵם, אֱמוֹר לוֹ צֵא מֵהֶם גּוֹי שֵׁנִי שֶׁאֵינוֹ עוֹלֶה מִן הַמִּנְיָן. רַב אָבִין אָמַר, בִּשְׁמוֹ גּוֹאֲלָן, שֶׁשְּׁמוֹ שֶׁל הַקָּדוֹשׁ בָּרוּךְ הוּא ע"ב אוֹתִיּוֹת. וְאַחֲרֵי כֵן יֵצְאוּ בִּרְכוּשׁ גָּדוֹל, אַחַר אֵין כְּתִיב כָּאן, אֶלָּא אַחֲרֵי מִשֶׁאָבִיא עֲלֵיהֶן עֶשֶׂר מַכּוֹת לְאַחַר כֵּן יֵצְאוּ. אָמַר לוֹ אַף אֲנִי בְּשִׁעְבּוּד, אָמַר לוֹ, וְאַתָּה תָּבֹא אֶל אֲבֹתֶיךָ בְּשָׁלוֹם תִּקָּבֵר בְּשֵׂיבָה טוֹבָה. אָמַר רֵישׁ לָקִישׁ, שְׁלֹשָׁה הֵן שֶׁכָּתוּב בָּהֶן בְּשֵׂיבָה טוֹבָה, אַבְרָהָם וְדָוִד וְשָׁוֶה לָהֶן גִּדְעוֹן וְלֹא שָׁוֶה לוֹ לָמָּה, (שופטים ח, כז) "וַיַּעַשׂ אוֹתוֹ גִּדְעוֹן לְאֵפוֹד", לַעֲבוֹדָה זָרָה.