When Gaal saw the people, he said to Zebul, Behold, there come people down from the tops of the mountains. Zebul said to him, You see the shadow of the mountains as if they were men.
In other words, he's an outsider. We ought to be serving Hamor and his family, let them be the kings. And he said to God the people were under my rule, because I can really do a good job here, you know. Who's Abimelech? And so he said if you would just commit yourself to me I would remove Abimelech.