You find that Abraham lived a hundred and seventy-five years, while Isaac lived a hundred and eighty. Those five years that the Holy One, blessed be He, withheld from Abraham's life were on account of the five transgressions that Esau committed. The Holy One, blessed be He, said: thus I promised Abraham, "And you shall go to your fathers in peace; you shall be buried in a good old age" (Genesis 15:15). Is this a good old age — that he should see his grandson worshiping idols, committing sexual immorality, and shedding blood? Better that he depart in peace. This is what is written, "Your steadfast love is better than life" [Abraham's shortened life was itself a kindness] (Psalms 63:4). "Let me gulp down" (Genesis 25:30) — he opened his mouth wide [demanding to be fed like an animal], and so on (as written in remez 109).
The Five Years God Took From Abraham as a Mercy
Yalkut Shimoni on Torah 110:32
אַתָּה מוֹצֵא אַבְרָהָם חַי מֵאָה וְשִׁבְעִים וְחָמֵשׁ שָׁנָה וְיִצְחָק מֵאָה וּשְׁמוֹנִים אֶלָּא אוֹתָן חָמֵשׁ שָׁנִים שֶׁמָּנַע הַקָּדוֹשׁ בָּרוּךְ הוּא מֵחַיָּיו, מִפְּנֵי חָמֵשׁ עֲבֵרוֹת שֶׁעָשָׂה אָמַר הַקָּדוֹשׁ בָּרוּךְ הוּא כָּךְ הִבְטַחְתִּי אֶת אַבְרָהָם (בראשית טו, טו) "וְאַתָּה תָּבוֹא אֶל אֲבוֹתֶיךָ בְּשָׁלוֹם תִּקָּבֵר בְּשֵׂיבָה טוֹבָה", זוֹ הִיא שֵׂיבָה טוֹבָה רוֹאֶה בְּנוֹ עֲוֹבֵד עֲבוֹדָה זָרָה, וּמְגַלֶּה עֲרָיוֹת, וְשׁוֹפֵךְ דָּמִים, מוּטָב לוֹ שֶׁיִּפָּטֵר בְּשָׁלוֹם. הֲדָא הוּא דִכְתִיב " טוֹב חַסְדְּךָ מֵחַיִּים". (בראשית כה ל) הַלְעִיטֵנִי, פָּעַר פִּיו וְכוּ' (כִּדְכָתוּב בְּרֶמֶז ק"ט).