The Torah relates that both Avraham and Lot were so heavily laden with livestock that it got to a point that there was not enough grazing land for all their animals. Consequently, a fight broke out between Avraham's shepherds and Lot's shepherds. The Torah continues with Avraham's reaction to the dispute: "And Avraham said to Lot, 'Please let there not be a fight between you and me and between your shepherds and my shepherds because we are brothers'" (Bereishis 13:8). Rashi cites the Medrash which explains that when he said "we are brothers" he was not referring to their blood relationship but rather to their facial resemblance.
The question begs to be asked. Why is the fact that they looked alike a reason that they shouldn't fight? Rav Wolbe (Shiurei Chumash, Parashas Lech Lecha) explains that the physical body is a representation of the neshama. The connection of the body and the soul does not work like super glue which has the ability to attach two totally dissimilar things to each other. Rather, one's facial features are merely a physical manifestation of the spiritual force from which they stem. In a similar vein, Chazal tell us that every physical dimension has a spiritual counterpart: "Every blade of grass has an angel who hits it and tells it to grow" (Bereishis Rabbah 10:6).
Since Avraham's and Lot's external appearance was similar, they shared similar internal spiritual qualities. When Avraham begged Lot not to fight, "because we look alike," he was informing his nephew that they shared a focal point in their avodas Hashem - the middah of chessed. This was certainly a reason that they should stay as far away from fighting as possible.
Earlier in the above story, the Torah tells us, "And Lot, who was traveling with Avraham, also had sheep, cattle and tents" (ibid. 13:5). Rashi explains that the cause of Lot's affluence was "his traveling (his close relationship) with Avraham." Where did Rashi see this explanation in the pasuk? Rav Wolbe explains that the Torah does not simply tell us stories. If the Torah informs us that Lot was traveling with Avraham, there must be a reason behind this piece of information. It was this association that brought about his acquisition of "sheep, cattle and tents." Once again, the Torah is directing our focus to the spiritual source. Lot's wealth wasn't simply by chance or due to his business acumen. His financial success was an expression of a spiritual source which came as a direct result of his connection with Avraham. Everything physical or material could be traced back to its spiritual source.
This idea is made clear in the following story. On one of Maran Harav Shteinman's trips to Chutz La'aretz, he was asked why we need so many men learning in kollel. After all, fifty years ago (and probably throughout most of our history) there was not nearly such a high percentage of men learning full time. He responded, that in truth, the opposite question should be asked. Baruch Hashem the Jewish People has many affluent members. Why do we need such a high percentage of wealthy Jews when throughout our history we never had so many affluent Jews? He explained that the reason there are so many wealthy Jews is only because there are so many men learning who need to be supported. If there would be fewer men learning there would also be less money to go around! Spiritual bounty generates material prosperity!