The three main emphases of Joshua – the possession of the land, obedience to the commands of Moses, annihilation of the peoples of the land – articulate conventional markers of group identity: possession of territory, proper religious practice, ethnic separation. As the plot moves from beginning to end, each of these markers is affirmed (claims that Israel possessed the entire land, obeyed all the commands of Moses, obliterated all the peoples) and compromised (reports of unoccupied land, disobedience to the commands, remaining peoples), rendering each an unstable element of national identity. As the narrative reaches its conclusion, only the covenant, in which the people choose the God who has chosen them, is left as a defining characteristic. Understood in this way, Joshua does not legitimize religious and ethnic violence, but rather undercuts claims of divine sanctions for such agendas.
by L.D. Hawk from Dictionary of the Old Testament: Historical Books, published by InterVarsity Press.