Tertullian

“ There is no agreement between the divine and the human sacrament, [2] the standard of Christ and the standard of the devil, the camp of light and the camp of darkness. One soul cannot be due to two masters—God and Cæsar. ”

“ But now inquiry is made about this point, whether a believer may turn himself unto military service, and whether the military may be admitted unto the faith, even the rank and file, or each inferior grade, to whom there is no necessity for taking part in sacrifices or capital punishments. ”