This article evaluates Origen's criticism of Christian participation in the Roman army in relation to two prominent themes in his writings: the moral progress of the Christian and the role of demons in God's providence. I argue that, for Origen, to be a Christian is to be a soldier, albeit one whose adversaries are not human combatants, but the Devil and his angels. The battle is won when Christians refrain from sinning, attaining moral perfection through their study of the scriptures, and adoption of ascetic practices. By avoiding the physical battlefield, Christians remain unsullied by the passions that inflame the soldier, enabling them to fight demons more effectively. But this spiritual combat is not without risks to the physical body. As Origen's Exhortation to Martyrdom attests, execution could be the providentially ordered outcome of a Christian's combat against demons. Origen presents the violent persecution of Christians as consistent with divine providence and martyrdom as a gift of God to the church. His opposition to Christian military participation is rooted neither in a wholesale rejection of warfare nor a deep respect for embodied life, but in his concern for human moral progress—progress that could be advanced by providentially sanctioned violence.