When speaking of Lot in posuk 12 the Torah uses the term “and he was living”; when speaking of Avrom in posuk 13 the Torah uses the term “and he dwelt”. These phrases contrast the attitudes of Avrom and Lot in their relations with their neighbors. The posuk tells us that Avrom remains the Ivri, which means “one who stands on the other side”, whether this means spiritually in opposition to the whole world, or geographically from across the river, he was known as an outsider. The Torah describes this relationship to his neighbors with the term “and he dwelt”, while regarding Lot it says “and he was living”. There is a difference between these two terms: “to live” means to belong completely to the place where you are, while “to dwell” means to be part of a social relationship with the inhabitants, to live in peaceful coexistence, without being entirely entwined with each other.
This behavior of Avrohom should serve as a model to his descendants. The Jew wherever he may find himself remains a Jew, yet he in no way disturbs the peaceful conditions he finds. He develops and arranges his own Jewish behavior in such a way that others want to draw him into their circle of friends, and not the reverse.