The aim of Arab war against Jews was complete extermination of Jews in Israel and they requested Arabs in the area to leave with the promise that they can get part of Jewish property when they return after the war.

Many still stayed and large part of them participated in attacks against Jews (in a genocidal war, mind you) and decided to flee when the war was decided in fear of retribution. How many of them figured it out on their own and how many had to be reminded by active measures, is disputed.