Volf argues in his book that "the Christian faith is misused when it is used to underwrite violence" (p.51). I must say that I agree. The biblical record seems clear to me that Christians are not to involve themselves in violence even in self-defense. I know that statement will draw the ire of some of my brothers and sisters.
Let me share a few examples: Jesus said turn the other cheek (Matt. 5:39); love your enemies (Matt. 5:44); be salt and light to the world (Matt. 5:14-16); imitate Christ in the way of self-sacrificial love (John 15:12-13; 13:34-35); carry our own cross (Matt. 10:38-39); imitate Christ in suffering and not retaliate (1 Peter 2:21-23). These are just a few among many others.
Also, a theme of the OT that's reiterated in the NT is this: The battle belongs to the Lord. It is not yours or mine to fight. Volf states in his book: "Though imitating God is the height of human holiness, there are things that only God may do. One of them is to deploy violence" (p.50). When a Christian picks up a weapon with the intend to harm another rather than picking up the cross to follow Christ then something is out of alignment.
From this some questions arise. How did we get here? How have Christians allowed the faith to become acquainted with violence? How do prevent this from happening further? Volf answers these questions by examining convictions and where they are rooted. Where we place our convictions makes a huge difference. Volf writes:
"If we strip Christian convictions of their original and historic cognitive and moral content and reduce faith to a cultural resource endowed with a diffuse aura of the sacred, in situations of conflict we are likely to get religiously legitimised violence. If we nurture people in historic Christian convictions that are rooted in its sacred texts, we will likely get militants for peace. This, I think, is a result not only of a careful examination of the inner logic of Christian convictions; it is also born by a careful look at actual Christian practice" (p.51).Ultimately, when we look at the character of the Christian faith and its fundamental convictions we see that they are not violence inducing. In fact, taken at face value they are just the opposite. When Christ calls a person, he bids them to come and die, not to go out and kill. When Christians get this backwards not only does the faith become coercive, but it also fails to imitate Christ.