Privily - See the margin. The word is probably the name of a place in "Tormah", some think the same as "Arumah" Judges 9:41. Zebul was faithful to Abimelech, but dissembled his sentiments, from being too weak to oppose Gaal, until Abimelech came with his army Judges 9:38.

They fortify the city against thee - Under pretense of repairing the walls and towers, they were actually putting the place in a state of defense, intending to seize on the government as soon as they should find Abimelech coming against them. Fortifying the city may mean seducing the inhabitants from their loyalty to Abimelech.

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, Judges 9:36 though, according to Joseph Kimchi and Ben Gersom, Thormah is the name of the place where Abimelech was, the same with Arumah, Judges 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.

And he sent messengers unto Abimelech privily, saying, Behold, Gaal the son of Ebed and his brethren be come to Shechem; and, behold, they fortify the city against thee.

privily: Heb. craftily or, to Tormah

9:30-49 Abimelech intended to punish the Schechemites for slighting him now, but God punished them for their serving him formerly in the murder of Gideon's sons. When God uses men as instruments in his hand to do his work, he means one thing, and they another. That, which they hoped would have been for their welfare, proved a snare and a trap, as those will certainly find, who run to idols for shelter; such will prove a refuge of lies.