וְתָּא חֲזֵי, לָא זָכָה יִצְחָק כְּאַבְרָהָם, דְּלָא סָמוּ עֵינוֹי וְלָא כָּהוּ. אֲבָל רָזָא עִלָּאָה אִיהוּ הָכָא, רָזָא דִּמְהֵימְנוּתָא. כְּמָה דְאִתְּמָר, דִּכְתִיב וַיִּקְרָא אֱלֹהִים לָאוֹר יוֹם, דָּא אַבְרָהָם, דְּאִיהוּ נְהוֹרָא דִימָמָא. וּנְהוֹרָא דִילֵיהּ אָזִיל וְנָהִיר וְאִתְתַּקַּף בְּתִקּוּנָא דְיוֹמָא. Observe now that Isaac was not so fortunate as Abraham, whose eyes were not blinded nor dimmed. Herein is a profound lesson touching faith, as has already been explained elsewhere. By “the light” here is meant Abraham, who is the light of the day and whose light keeps on expanding and growing stronger like that of the day.

וּבְגִין כָּךְ, מַה כְּתִיב, (בראשית כ״ד:א׳) וְאַבְרָהָם זָקֵן בָּא בַּיָּמִים, בְּאִינוּן נְהוֹרִין דְּנָהֲרִין. וְאִיהוּ סִיב, (ד"א ל"ג ונהיר כדין אזיל ונהיר) כְּמָה דְאַתְּ אָמֵר, (משלי ד׳:י״ח) הוֹלֵךְ וְאוֹר עַד נְכוֹן הַיּוֹם, וּבְגִין כָּךְ, (בראשית א׳:ה׳) וַיִּקְרָא אֱלהִים לָאוֹר יוֹם. וְלַחשֶׁךְ קָרָא לָיְלָה, דָּא יִצְחָק דְּאִיהוּ חשֶׁךְ, וְאִיהוּ אָזִיל לְקַבְּלָא לֵילְיָא בְּגַוִּיהּ, וּבְגִין כָּךְ, אִיהוּ כַּד סִיב, מַה כְּתִיב, (בראשית כ״ז:א׳) וַיְהִי כִּי זָקֵן יִצְחָק וַתִּכְהֶיןָ עֵינָיו מֵרְאוֹת. הָכִי הוּא וַדַּאי, דְּבָעָא לְאִתְחַשְּׁכָא וּלְאִתְדַּבְּקָא (בחשך) בְּדַרְגֵּיהּ כְּדְקָא יְאוּת. Hence it is written: “And Abraham was old, advancing in days” (Gen. 24, 1), that is, in illumination, and as he grew older his light continued to expand, so that he was “shining more and more unto the perfect day” (Prov. 4, 18). On the other hand, “the darkness” is a description of Isaac, who represents darkness and night, and hence when he was old his eyes were dim, so that he could not see. He had to become enveloped in darkness in order to become attached to his own proper grade.’

אֲתָא רִבִּי אֶלְעָזָר בְּרֵיהּ, וְנָשִׁיק יְדוֹי. אָמַר לֵיהּ, שַׁפִּיר, אַבְרָהָם נָהִיר מִסִּטְרָא דְּדַרְגָּא דִילֵיהּ, יִצְחָק אִתְחֲשָׁךְ מִסִּטְרָא דְּדַרְגָּא דִּילֵיהּ, יַעֲקֹב אַמַּאי, דִּכְתִיב, (בראשית מ״ח:י׳) וְעֵינֵי יִשְׂרָאֵל כָּבְדוּ מִזֹּקֶן. אָמַר לֵיהּ, הָכִי הוּא וַדַּאי, כָּבְדוּ כְּתִיב, וְלֹא כָּהוּ. מִזֹּקֶן כְּתִיב, וְלָא מִזִּקְנוֹ. אֶלָּא מִזֹּקֶן, מִזֹּקֶן דְּיִצְחָק, מֵהַהוּא סִטְרָא כָּבְדוּ. לֹא יוּכַל לִרְאוֹת, לְאִסְתַּכָּלָא כְּדְקָא חָזֵי, אֲבָל לֹא כָּהוּ. אֲבָל יִצְחָק כָּהוּ וַדַּאי מִכֹּל וָכֹל, וְאִתְעֲבִיד חשֶׁךְ, דְּהָא כְּדֵין אִתְאֲחִיד בֵּיהּ לַיְלָה, וְאִתְקַיָּים וְלַחשֶׁךְ קָרָא לָיְלָה. R. Eleazar his son came and kissed his hand. He said: ‘So far I understand. Abraham was bathed in light from the side of his grade; whereas Isaac became wrapt in darkness from the side of his grade. But why is it written of Jacob: “And the eyes of Israel were heavy for age” (Gen. 48, 10)?’ R. Simeon in answer said: ‘It is written here “they were heavy”, but not “they were dim”; and further, it is not written “for his old age”, but “for old age”, referring to the old age of Isaac, and implying that his eyes were heavy as a result of the side of Isaac, but still they were only so heavy as to prevent him seeing properly, but not entirely dim. Whereas Isaac’s eyes were altogether dimmed, so that darkness settled upon him and night took hold of him, until to him could be applied the words, “And the darkness he called night.”