John Gill Commentary Joshua 9:2

"that they gathered themselves together, to fight with Joshua and with Israel, with one accord." — Joshua 9:2 (ASV)

That they gathered themselves together to fight with Joshua ,
and with Israel
Not at this time, but they met together to consult what was proper to be done in order to secure themselves, and their people, and put a stop to the successes of the arms of Israel; and for this purpose entered into alliances with each other to assist one another, or at a convenient time and place to join their forces together, and attack Israel, as afterwards they did, (Joshua 11:1–5); and this they did

with one accord;
were unanimous in their councils and resolutions; they all confederated together, and agreed as one man to make a common cause of it, and oppose Israel with their united forces.