It states in this week’s parashah (13:7-8), ויהי לוט אל אברם ויאמר ...לוט מקנה רועה ובין אברם רעי בין ריב וביניך ביני מריבה תהי נא אל, “There was an argument between Avram's shepherds and Lot's shepherds... Avram said to Lot, "Let there not be a dispute between us..."
The Shlah HaKadosh notes that the pasuk (ibid.) begins with the word ריב and ends with מריבה. Both words mean dispute. The difference between the two is that מריבה is in feminine form, implying that the dispute can chalilah increase in intensity and multiply, while ריב is the masculine form of the same word, which implies that the argument will not grow out of proportion. There was a ריב between the shepherds, and Avram requested מריבה תהי נא אל, let's be careful that this dispute doesn't turn into something greater. Let's stop this machlokes now, so it doesn't bear fruit and create a great rift between us.
The Gemara says, חסרת מה קנית דעה which can be translated to mean that someone with daas, wisdom, חסרת מה, will take the letters ה"מ out of מריבה. When the letters ה"מ are taken out of מריבה, the word becomes ריב, the masculine form of dispute. The wise are cautious that a fight remains small and insignificant making sure that it doesn't grow and get out of hand.
As it states (Mishlei 17:14), מדון ראשית מים פוטר, "Like water gushing through an opening, is the beginning of a dispute." Rashi (Sanhedrin 7.) explains, "When a river swells, it flows to the fields along the banks. The flow goes through narrow furrows and channels. If the flow isn't stopped immediately, it will become stronger and wider until it can't be stopped. This is the nature of a dispute..." If it is not stopped at the onset, it becomes larger and overpowering.
The Shlah said that this is alluded to in the word מחלקת. The 'מ has a tiny opening, which represents a still small and narrow machlokes. The opening of the 'ח is wider, for the argument has become greater. 'ל is the tallest letter, going upwards, and 'ק is long downwards. This suggests that the machlokes is growing in all directions. And finally, 'ת, the machlokes stands firmly and securely on its own two legs.
All of this could be avoided if you stop the machlokes at the very beginning when it's still merely a tiny opening in the 'מ.
The Shlah HaKadosh (Yoma Derech Chaim 44) writes, פרנסות מאה דוחה אחת מחלוקת, "One machlokes drives away a hundred parnasos." The word כנען can mean poverty, as it states (Zecharyah 14:21), 'ה בבית עוד כנעני יהיה ולא צבאות, "There will be no more poverty..." Thus, the pasuk tells us, יושב אז ...והכנעני ...ריב ויהי בארץ, "there was a machlokes...and poverty... was then in the land." Machlokes causes poverty; unlike peace, shalom, which brings parnassah in abundance.
