From its earliest days, Christianity has debated about when and how force can be used to repel harm without incurring sin. Although moderation and restriction have often been advocated both on a personal and on a social level, strict passivity has rarely been the proposed solution in mainstream Christianity when individuals or nations are confronted with harm. The Just War tradition, in its many variations, was born precisely out of this desire to make sense of how force can be used in a Christian way. And it soon became the prevalent theory throughout Christianity to address issues of violence, war, and force in general. What this thesis intends to argue is that Just War theory, despite all its pervasiveness, is flawed in some crucial aspects when scrutinized from a Christian viewpoint. Three such aspects seem to be especially relevant: Just War tradition is not grounded enough in Scripture; its jus ad bellum and jus in bello criteria do not protect in a satisfactory way the innocent who face harm; and it is a theory that is only reactive to force being imposed upon others. Because of these three flaws, it will be claimed that in the process of giving its support to Just War theory Christianity has largely forgotten an older, broader tradition. The “be angry, but do not sin” tradition has Scriptural and philosophical roots that, when combined, can bring a Christian virtue ethics to a much better understanding of when and how forceful intervention in the social sphere is required. At the very least, this anger tradition does not fall prey to the three criticisms that are addressed towards Just War – and that seems to make it especially valuable. Righteous anger, then, and not Just War, should be what guides Christianity in its thinking about how and when force can be used without incurring sin. That is the contention of this thesis.