זוהר בראשית — דף קמב ע”א

The Zohar explains that “God called the light day” refers to Abraham, whose light grows ever brighter, and “the darkness He called night” refers to Isaac, hence “his eyes grew dim.” Rabbi Elazar notes that of Israel’s eyes it says “heavy,” not “dim.” On “Happy is the man whose strength is in You,” the text mentions Hananiah, Mishael and Azariah, and teaches that one should not say that God will save him, but place his strength in Him and strive in the commandments; “the highways are in their heart” is also read as Torah studied for God’s sake. Jacob acted for the sake of the Holy One, blessed be He, and the Divine Presence was with him; it informed Rebecca when Isaac called Esau. Rabbi Yose says that had Esau been blessed then, Jacob would never have prevailed; Rebecca then turns to Jacob: “Now, my son, listen to my voice.”