John Wesley on Joshua 17:16

Is not enough - Heb. the hill will not be found, that is, obtained by us; those fierce and strong people the Perizzites and the giants will easily defend themselves, and frustrate our attempts, having the advantage of the woods and mountains. The Canaanites that dwell - That is, and if thou sayest, that if the hill either cannot be conquered, or is not sufficient for us, we may go down and take more land out of the pleasant and fruitful valleys, we shall meet with no less difficulty there than in the mountains. Chariots of iron - Not all made of iron, but armed with iron, not only for defence, but for offence also, having as it were scythes and swords fastened to them, to cut down all that stood in their way.