That Yitzchak “trembled a very great trembling” is a powerful statement. The phrase implies an exceptional incident taking place which serves as a foreshadowing of the future. Pesikta D’Rav Kahana states that Yitzchak suddenly became aware of Eisav’s deception. The presence of Gehinnom — which Yitzchak felt when Eisav entered the room — caused Yitzchak to realize that he had erred terribly all these years. Had Rivkah not manipulated the course of events, maneuvering Yaakov to enter before Eisav, who knows what the disastrous outcome might have been? Indeed, the entire history of Klal Yisrael would have been severely altered….
