Genesis 13:6

And the land was not able to bear them.

Lot had shared Abraham's prosperity. They had come up out of Egypt with larger herds and flocks, and more "tents" for their numerous retainers. The land may not have fully recovered from the effects of the drought that had caused the famine; at any rate there was insufficient pasturage for such vast herds. These, scattered over the hills by thousands, would soon exhaust the grass anywhere within reach of the encampment, and their interests demanded. separation.