Avraham wandered to the land of Canaan at the command of God. Since he remained childless, he may have considered the possibility that his nephew Lot, who was accompanying him on his journey, would inherit him. But during the period that Avraham was in Egypt, Lot was exposed to a new way of life that captured his heart.

Avraham and Lot
Courtesy of the Virtual Beit Midrash, Yeshivat Har Etzion