When God commanded Israel to war, the primary reason was to inhabit the land. Obviously, this is no longer applicable to Christians. A secondary reason was purity; Israel had to cleanse the land of the original inhabitants lest they turn God’s people to foreign idols. However, now that God’s Kingdom is no longer geographically centred, there is no ability to physically separate from non-believers. While a possible logical conclusion would be for Christian to remove themselves from the surrounding society in some way, this is not the Biblical exhortation. Instead, purity is expressed in living different lives amongst them, and not conforming to the social pressures.
As Longman concludes: “The purpose and dynamic of sacred warfare in the Bible indicate that this theme cannot be used to justify war between nations today (although many Christians believe that war can sometimes be justified on other grounds). For God’s people spiritual warfare has replaced physical, and they are no longer a single nation; thus a modern war cannot be called Yahweh war.” (NDBT, Warfare) Cameron agrees that ‘the Bible’s story arc makes it clear that Christians are not to engage in “holy war”.’ (Joined Up Life, 132).