Joshua said to them, If you are a great people, go up to the forest, and cut down for yourself there in the land of the Perizzites and of the Rephaim; since the hill-country of Ephraim is too narrow for you.
Although the Joseph tribes received the best part of Canaan, they were still not satisfied. They wanted more land, but they did not want to work for it or fight for it. Joshua told them that if they cleared the forests and drove out the Canaanites, they would find that they had plenty of land within the territory already allotted to them (14-18).