Genesis 36:7 - Ellicott's Commentary On The Whole Bible

The land wherein they were strangers. — The large growth of their wealth made the separation of Esau and Jacob as inevitable as had been that of Abraham and Lot. It is a usual incident in the life of nomads, and a tribe can multiply only to the extent of the capabilities of their district to support them. When this is reached, one portion of the tribe must seek a new home. This necessity was in the present case aggravated by Esau and Jacob being only sojourners in Canaan, surrounded by tribes who claimed to be owners of the soil: and this may have helped in determining Esau’s choice; for in right of Aholibamah, he was in her country a duke. Maimonides also observes, that though Esau had gone on hunting expeditions to Seir, and even possibly for plunder, yet that he was not sufficiently powerful to take possession of the country until by Isaac’s death the number of his retainers was largely multiplied.