Мусар к Берешит 13:8

One must make great efforts to avoid personal strife. If a quarrel is in the offing, one must immediately strive to remove the cause of such quarrel, as our sages said in Sanhedrin 7 when commenting on Proverbs 17,14: פוטר מים ראשית מדון, "Starting a quarrel is like opening a sluice." Abraham demonstrated this virtue when he said to Lot: "let there not develop a quarrel between us." I detect a special meaning in Abraham employing the feminine form for the word strife, i.e. מריבה, although the Torah had already reported a "strong" quarrel, ריב, having occurred between their respective shepherds (Genesis 13,7). Abraham considered מריבה as a development of ריב. He considered the "fruit" of ריב to be מריבה. The latter word is akin to מתרבה, "constantly increasing." Since women produce children, he used the female form of the word ריב, i.e מריבה, in order to allude to the peculiarity of quarrels which keep increasing. He viewed ריב as something masculine, unable to give birth.

And behold Abraham our father distanced himself greatly from division that was not for the sake of Heaven. That is like he said to Lot, Let there be no strife between [us] (Genesis 13:8). And in the two [cases discussed previously], you will find division in two letters, specifically in bet and lamed. The [author of Sefer Ha] Pardes wrote that the shape of a bet is a dalet, with a vav below, after it, extending as a [horizontal] line, meaning the vav. And the hint in the thing is according to what he wrote there.