Sforno on Genesis 13:14/ספורנו על בראשית י״ג:י״ד

1אחרי הפרד לוט, G’d did not say what follows while Lot was still in Avram’s company, so that the latter would not boast and his shepherds would engage in stealing grazing land from the local inhabitants claiming G’d’s promise to Avram of future possession as their justification.