Matthew Poole and continuators on Genesis 13:7

7. And there was a strife between the herds-men of Abrams cattel, and the herds-men of Lots cattle: and the Canaanite , and the Perizzite dwelt then in the land .

(i. e.) The Canaanites, as Gen. 12. 6. the singular number for the plural, as Psal. 78. 45. and 105. 33, 40.

(i. e.) Were the Lords and Owners of it, and therefore Abram and Lot could not take what pastures they pleased, but such as the others left them, which was not sufficient for their conveniency. It may also be added as a reason of Abram's following motion, because that idolatrous people were present, and diligently observed all their contentions and other miscarriages, and would doubtless take occasion thence to disparage the true Religion. And it must be remembred, that these are the words not of Abram, but of Moses; who, knowing that the Canaanites were then speedily to be turned out of the Land, intimates that the case was otherwise in Abrams days, when the Canaanites were possest, and were likely to continue the Possessors and Lords of the Land.