John Gill Bible Commentary

And he sent messengers unto Abimelech privily,.... In a secret manner, unknown to Gaal and the men of Shechem; or "craftily", as Jarchi and Kimchi interpret it, still dissembling, notwithstanding his anger, to be in the interest of Gaal, and the men of Shechem, as appears indeed afterwards by a show of friendliness with Gaal, Jdg 9:36 though, according to Joseph Kimchi and Ben Gersom, Thormah is the name of the place where Abimelech was, the same with Arumah, Jdg 9:41 and the sense is, that he sent messengers to Abimelech at Thormah or Arumah: saying, Gaal the son of Ebal, and his brethren, be come to Shechem; a family that Abimelech well knew, and if they were of the race of the old Canaanites, he would easily perceive their design: and, behold, they fortify the city against thee; by repairing its fortifications, or adding new works; or "besiege" (i) it, which, as that is done by placing an army around it without, that none can come out of it, so by setting a watch within, and upon the walls, and at the gates of it, that none can come in, which is here meant; though some interpret it of their design to besiege the city Thormah, where Abimelech was, of which he gives him notice; or rather they set the city against thee, make the inhabitants thine enemies. (i) "obsident", Pagninus, Munster, Drusius; "obsidere cogitant", Piscator.