“...when the people of Joseph complain about their lack of land (17:14), Joshua’s response is to suggest that they boldly take more land. But it is land that is, they complain, associated with Rephaim, and with Canaanites with iron chariots. Their complaint here contrasts them with Caleb (possibly reflecting Num 13); Caleb went up against the Anakim and the large cities, whereas the Josephites are afraid to go up against the Rephaim and iron chariots. They lack the boldness and courage that should be exercised in the light of YHWH’s promise to possess the land. The story ends on a rather ambiguous note; Joshua gives them reassurance that they can do it—but will they?”—Reading Joshua as Christian Scripture, page 174
They have the promise in their hand, but they are afraid to step out of their comfort zone. Sounds only too familiar, doesn't it? God promise, we doubt. But, not Caleb, he took the promises and went after the reward—and obtained it. Would that we would all do the same with the promises we have been given...