רמב"ן — ויהי ריב בין רעי מקנה אברם

Q — Rashi (from Chazal) frames the dispute between the shepherds as a halachic argument over gezel: Lot's shepherds grazed in others' fields, Avram's protested, and the pasuk's 'והכנעני והפרזי אז יושב בארץ' is the Torah's verdict siding with Avram's shepherds. What's wrong with this?

A — Ramban's peshat: the rift was a practical grazing conflict — 'ולא נשא אותם הארץ' — Lot's herders encroached on Avram's territory because the land could not sustain both. The clause about the Kena'ani and Perizi is not a halachic verdict but a security warning: Avram feared that a concentration of two large flocks under one extended household would alarm the local populations, who might attack and seize everything. The rift had nothing to do with sin and tochecha. (Ramban adds an aggadic-historical reading of 'אז' — that the local nations followed a nomadic-pastoral rotation pattern, 'כמנהג בני קדר'.)