And Isaac sent Jacob, and he went to Padan aram, to Laban the son of Bethuel the Aramean, the brother of Rebecca, the mother of Jacob and Esau.We know that Rebecca is Jacob's and Esau's mother. Why does the Torah bother to mention this. There must be something to be learned from this seemingly useless repetition of something that we already know. Rashi, the Torah's foremost commentator, has a surprising answer:
I do not know what this teaches us.For someone of Rashi's stature to say, "I don't know" is a sign of great humility. But I think that there is more to this.
The Siftei Chachamim asks that if Rashi does not know what this comes to teach us, then why doesn't he just stay silent and not mention it? He answers that Rashi had several explanations, he just did not know which one was correct. I find this explanation hard to accept, for we see plenty of verses where Rashi offers multiple explanations. Here's one from this week's Torah portion:
It came to pass when Isaac was old, and his eyes were too dim to see, that he called Esau his elder son, and he said to him, "My son," and he said to him, "Here I am."Why did Isaac lose his eyesight? Rashi offers three explanations:
Because of the smoke of these [wives of Esau] (who would burn [incense] to the idols) (Tanchuma, Toledoth 8; Pesiktha Rabbathi 12). Another explanation: When Isaac was bound on the altar, and his father was about to slaughter him, the heavens opened, and the ministering angels saw and wept, and their tears fell upon Isaac’s eyes. As a result, his eyes became dim (Gen. Rabbah 65:6). A third explanation: to enable Jacob to take the blessings (Gen. Rabbah 65:8).I think that the answer to why Rashi wrote, "I do not know" is that he wanted assure the reader that indeed there is a difficulty in the text. When one learns Torah and he encounters a difficulty, he immediately looks to see if one of the great classic commentators had the same question. If none of our great rabbis asked the question, that may be a sign that he is not learning well, that he is "way off". So here Rashi is telling us that there is a question to be asked here, and that one who asks it is learning well!