Or HaChaim on Genesis 27:5/אור החיים על בראשית כ״ז:ה׳

1 ורבקה שומעת, and Rebeccah was listening, etc. The Torah tells us that Rebeccah was a prophetess who always listened to Isaac's words even though she did not speak up in his presence. The. Torah alludes to this by saying ורבקב שומעת בדבר יצחק, "Rebeccah was listening whenever Isaac spoke." Normally we would have expected the Torah to write: ותשמע רבקה, "Rebeccah happened to overhear." The present tense employed here by the Torah here is most unusual. Maybe Isaac spoke to Esau in a whisper and that is why he believed that Jacob was really Esau; Isaac thought that Jacob could not have have heard of Isaac's instructions to Esau. Although Isaac's eyesight had begun to fail him, he called Esau to help him with something confidentially. Both Isaac's call and Esau's response, "I am ready" may be an allusion to the conspirational nature of the conversation.