Rabbeinu Bechaye uses a Pasuk in Mishlei to describe Avraham Avinu. The text from Chaper 13 reads as follows: “One who walks with the wise will grow wise, but the companion of fools will cause evil.”
There is a very strong message learned from לך לך. It was not possible for Avraham Avinu to become a great leader and come close to Hashem, in אור כשדים. There were too many negative influences and the place was filled with idol worshippers. In Eretz Yisrael, he would thrive and become the father of a great nation.
We must learn this lesson. Everyone is affected by their environment. It is virtually impossible to remain an island in a sea of materialism that lacks spirituality. Each of us has to do his own לך לך to be certain he lives among those striving to improve themselves and come closer to G-d.