The Sages describe the encounter between Esau and Isaac immediately after Jacob received the blessing from Isaac, and the reaction of Esau and Isaac after they realized that it was Jacob who was blessed.

“And Jacob had just departed from the presence of Isaac his father” (Genesis 27:30). This one, Jacob, exited and that one, Esau, entered. How could that matter have transpired? One who is located in the light does not see one who is located in the relative darkness, but one who is located in the relative darkness sees one who is located in the light. Esau came from outside and did not see Jacob, who was inside the house; but Jacob saw Esau from inside and hid behind the door. Once Esau entered, Jacob emerged from his hiding place and left, as it is stated: “And Jacob had just departed from the presence of Isaac his father and Esau his brother came from his hunt” (27:30). Did Jacob estimate the hours so precisely that Esau would not come and take the blessings? When Esau went out to hunt, the Holy One, blessed be He, sent an obstructer against him and did not enable him to trap until Jacob came and took the blessings…. How so? Esau would run and trap a deer and tie it and leave it, and would run and trap another and tie it and leave it, and the obstructer would untie them and release them, and Esau would come and would not find either of them. Thus the obstructer did two or three times…and the obstructer delayed Esau until Jacob came and took the blessings. At that moment that Esau arrived to receive his father’s blessing, Isaac recognized Esau’s voice and began trembling. Isaac said to him: Who are you? Because at the moment that Jacob entered, the pleasing aroma of the Garden of Eden entered with him, and the mind of that righteous man Isaac was relaxed, as it is stated: “See, the scent of my son is as the scent of a field that the Lord blessed” (27:27). Therefore, Isaac began blessing Jacob. But when Esau entered, Gehenna opened before Isaac;(Tanĥuma [Buber], Toledot)