Synopsis of the Books of the Bible, by John Nelson Darby, [1857-62], at sacred-texts.com
Here (chap. 26) Isaac replaces Abraham as heir upon the earth. It is a new revelation, when Isaac is himself in a strange land, like the one made to Abraham at the first; only that Isaac was already in connection with the calling of God, but not in enjoyment of the promise. There was a famine in the land, and Isaac could not dwell in it, and he goes to those who had part of the land in possession, but had no title the future enemies and oppressors of his people. But God appears to him there, and tells him not to return into the world, but to dwell in the land which He should tell him of. He is maintained in the heavenly places, but still as a place of promise, though not now seeking it as unknown, but still as an object of faith. It was a fresh calling under different circumstances (the Lord appearing to him anew), not indeed to journey to a land, but to dwell where He should shew him, and not to seek natural resources (Egypt). He was not to go back, but to live by faith. But the land is also shewn and the promises renewed, both as to Israel, and the nations, and the land. For the moment he was to sojourn in the land where he was, that is, where the Philistines were. Thus the whole land, Philistines and all, was given to him, and he dwelt in Gerar.
This is the position of Isaac; as the first half of chapter 12 is the position of Abraham. From Verse 7 to the end we have his personal walk as to faith, as Abraham's in the latter part of chapter 12; and the settlement of what should be his portion in his posterity according to the faith that he had. He fails like Abraham, and yet more as to energy. He denies his wife, as Abraham had done, and he leaves in the hand of the enemy the wells which Abraham had dug: he had failed in faith in God before Abimelech, and, though God had said to him "Sojourn in this land," he has to recede before the will of Abimelech, then driven from well to well, and has room only where the Philistine has room. In Beersheba he meets with God, where he has pitched his tent, where Abraham had set his bounds with Abimelech when Isaac was born. But Abraham had not received direction as to sojourning in the land, and had reproved Abimelech, whose servants had taken the well and Abimelech had given it up. Abraham had dug all these wells as he needed, as a stranger, and they were not taken away: the only one contended for was Beersheba, and that Abimelech gave up. However Beersheba was, in divine providence, the limit of the land according to the faith of Israel. The Philistines did remain till David came, the representative of Christ. The otherwise heirs of the land possessed it not fully. There the Lord appeared and blessed Isaac: there Israel reposed and worshipped. This chapter is Isaac's history; it answers to Abraham's (chaps. 12, 20).
Esau's ways were as careless, as his thoughts as to the birthright were profane. He marries with the women of the land.