וַיְהִי֙ כִּֽי־זָקֵ֣ן יִצְחָ֔ק וַתִּכְהֶ֥יןָ עֵינָ֖יו מֵרְאֹ֑ת וַיִּקְרָ֞א אֶת־עֵשָׂ֣ו ׀ בְּנ֣וֹ הַגָּדֹ֗ל וַיֹּ֤אמֶר אֵלָיו֙ בְּנִ֔י וַיֹּ֥אמֶר אֵלָ֖יו הִנֵּֽנִי׃
און עס איז געװען, אַז יצחק איז אַלט געװאָרן, און זײַנע אױגן זײַנען געװאָרן צו טונקל צו זען, האָט ער גערופֿן זײַן עלטערן זון עֵשָׂון, און האָט צו אים געזאָגט: מײַן זון! האָט ער צו אים געזאָגט: דאָ בין איך.
Megillah
R Elazar further said in the name of R. Hanina: Let not the curse of an ordinary man be held lightly in your eyes, because Avimelech cursed Sarah, saying, “Behold he is for you a covering of the eyes” (Genesis 20:16) and this was fulfilled in her seed, [as it says], “And it came to pass that when Isaac was old his eyes were dim” (Genesis 27:1).
Megillah
His eyes become dim, as it says, “And it came to pass that when Yitzchak grew old that his eyes became dim, so that he could not see” (Genesis 27:1). Because he used to look at the wicked Esau.