Kabbalah su Genesi 26:8

"And it came to pass, when he had been there a long time with Rivkah his wife" (Beresheet 26:8): "with (Heb. et) Rivkah his wife," precisely, which alludes to the Shechinah that was with Rivkah, because Et ('with'), as we know, is the name of the Shechinah. Another explanation asks if we could possibly conceive of Isaac performing his marital duties during the daytime. We have learned that the children of Yisrael are holy and abstain from cohabitation in the daytime. Therefore, how could Isaac, who was holy, cohabit during the day?

Assuredly Abimelech was wise and looked at the wisdom of the stars, that is called a 'window', as it is written here, "out at a window" (Beresheet 26:8), and elsewhere, "The mother of Sisra looked out at a window" (Shoftim 5:28). As there (refers to) astrology, so here to astrology. And he saw there that it was not as Isaac said, but that he surely was sporting with her, and she was his wife. Then, "Abimelech called Isaac" (Beresheet 26:9) Rabbi Yosi said that it would have befitted Abimelech to do this to Isaac, as he did to Abraham, were it not for the Holy One, blessed be He, who reproved him earlier.