Charles Ellicott Commentary Genesis 36:7

"For their substance was too great for them to dwell together; and the land of their sojournings could not bear them because of their cattle." — Genesis 36:7 (ASV)

The land wherein they were strangers. —The large growth of their wealth made the separation of Esau and Jacob as inevitable as that of Abraham and Lot had been. It is a usual incident in the life of nomads, and a tribe can multiply only to the extent of its district's capabilities to support it. When this limit is reached, one portion of the tribe must seek a new home.

This necessity was, in this case, aggravated by Esau and Jacob being only sojourners in Canaan, surrounded by tribes who claimed to be owners of the soil. This circumstance may have helped determine Esau’s choice, for by right of Aholibamah, he was a duke in her country.

Maimonides also observes that although Esau had gone on hunting expeditions to Seir, and possibly even for plunder, he was not sufficiently powerful to take possession of the country until Isaac’s death, when the number of his followers was largely multiplied.