כי הקרה ה' אלהיך לפני. כשם שהעבד שהלך לבקש לך אשה אמר הקרה נא לפני היום וגם האיל שנזדמן בעקידתך לפי שעה כך הקרה לפני בשבילך: כי הקרה ה' אלוקיך לפני, “because the Lord your G–d has so arranged it for my benefit on this day.” Esau used the same phraseology that Eliezer had used when on his way to find a wife for Yitzchok (Genesis 24,12) The ram which was entangled by its horns in Genesis 22,3 was also something that G–d had made happen just for that occasion, so that Avraham would not feel that he had come all the way without G–d accepting an offering from him. The root קרה occurs only in connection with things which occurred without visible preparation for use at a certain moment. (B’reshit Rabbah, 65,19) According to the Midrash there, the moment the person before him used the tetragram when referring to G–d, Yitzchok knew that that person could not be Esau.