Why did Yitzchak go to the well of Lachai Ro'i? Where did he come from?
Rashi: He went there to bring Hagar back to Avraham, to remarry her. 1
Seforno: He went to Daven 2 at the same spot where Hagar (his maidservant) had been answered.
Rashbam and Ramban: The well was situated in the south of Eretz Kena'an, which is where Yitzchak was currently living, as the continuation of the Pasuk indicates. 3
Ramban (citing Targum Onkelos); He came there from Be'er-Sheva (in the south), where Avraham and his family were currently living. That is where he brought Rivkah after they met in the field.
Targum Yonasan: He actually came from the Beis-ha'Midrash of Shem, where he had been studying for three years since the Akeidah 4 - which was situated in the south 5 in the vicinity of the well of Lachai Ro'i, by which HaSh-m, who sees but cannot be seen, revealed himself to Hagar.
Malbim: The well was in the south, between Kadesh and Bared (16:14), which is where Avraham went after Sedom was destroyed (20:1), and Yitzchak was living now. He used to go there every afternoon to meditate alone, and pray Minchah at the place where an angel appeared to Hagar.
Ha'amek Davar: He was living in Be'er-Sheva with Avraham. Due to Hashgachah, he had gone to Be'er Lachai Ro'i, and Rivkah saw him and was awestruck by his appearance. Had she first come to Avraham's house and talked with him, she would not have been mesmerized when she saw Yitzchak, and would have conducted with him like any wife does with her husband. 6
Refer to 25:1:1. Oznayim la'Torah - We can learn from here that, after the death if their mother, children should not stop their father from remarrying (or their mother after the death of their father).
See also 16:7 and 20:1.
If in fact the Yeshiva of Shem and Ever was situated in the south, near Be'er Sheva, this may explain why Avraham went to Be'er Sheva after the Akeidah (22:19), although he lived in Chevron - to arrange provisions for Yitzchak who would study there. It also may explain how in the opening verse of Parshas Va'Yeitzei, Yaakov left to Charan from Be'er Sheva (28:10), and not from Chevron where Yitzchak [usually] lived (35:27) - for until that point, he had been studying for 14 years at the Yeshiva, which was in the vicinity. Also refer to 23:2:1:1; refer to 28:10:2:3. (CS)
Ha'amek Davar (24:65): Her fear of him became fixed in her heart, and her entire life she could not argue with him - when she saw that Eisav is tricking him, in contrast to Sarah and Rachel, who had occasion to speak boldly to Avraham and Ya?akov, respectively.
QUESTIONS ON RASHI
Rashi writes: "[Yitzchak] dwelt in the land of the Negev - near that same well." But Rashi himself cites that the Negev was "between Kadesh and Shur" (20:1), while Be'er Lachai Ro'i was "between Kadesh and Bared" (16:14)?
