This research develops questions that relate Christianity and the military in the canon of the New Testament and in the Fathers of the Church. In order to provide a necessary contextual framework, a study was held regarding military activity in the Roman Empire, investigating its evolution over the centuries and referring the main characteristics of this service. In the canon of the New Testament, this work will provide an investigation about the intentional treatment of the military in Lucan s work due to the influence the role of the centurion Cornelius will play in the theological question of the admission of the Gentiles into the Church. The military language in Pauline letters is approached in its varied use, as a metaphorical sense, as a military rhetorical resource and in the images that accompanies the Pauline eschatology based on the Old Testament hope. Finally, this dissertation presents the emerging of the military question on the Fathers of the Church, specially on Tertullian and Origen, deepening the reasons that led them to oppose military service.