One fashion in current discussion of Christian attitudes toward war and peace is to hold that the early church was pacifist and that acceptance of the possibility of military service for Christians came only with the emergence of just war thought in the fourth century. On this view the denial of military service to baptized Christians is more essentially Christian because more primitive, and the acceptance of such service comes to pass only as a result of compromises the church made with the secular world during and after the time of Constantine. This interpretation of the first four centuries of Christian history first appeared concretely in the radical wing of the Reformation; it has since been used at many stages in the developing interaction between Christian just war and pacifist thought as “proof” that if Christians would be true to their origins, they must reject things military not only for themselves, but implicitly for the world. On this view the idea of a “Christian solider” is a contradiction in terms.
There are, however, a good many difficulties with this interpretation of early Christian attitudes toward military service. The development of a positive morality for a Christian soldier is indeed one feature of just war thinking, but that development should not be thought of narrowly as a product of the immediately post-Constantinian age. Its roots may reach earlier, and in any case the working out of such a morality has been under way ever since. As to whether pacifism was in fact the normative position of the early church, the evidence is much more skimpy and much more mixed than the interpretation sketched above suggests. At the very least it is clearly wrong to find in early Christianity a similar kind of rejection of things military to that found in the pacifism of the Radical Reformation or that of contemporary Christian pacifists. Let us look more closely, first, at the early Christians and second, at the development of a morality for the Christian soldier.
While clearly neither Jesus nor any of his original twelve disciples were soldiers, among the persons to whom the gospel was first preached and among the first converts were people in military service. The point is often made that there is no evidence from the earliest sources that converted soldiers continued in military life after baptism or that baptized Christians later became soldiers; the first hard evidence of Christian soldiers is the case of the so-called “Thundering Legion” around the year 174. Roughly a generation later Tertullian’s “Of the Soldier’s Crown” reflects the presence of Christian soldiers in the Roman army in North Africa; after this the number grows apace until finally, beginning with Constantine about another century later, only Christians could be soldiers. The first steps toward a Christian just war doctrine (developing out of older Roman and Old Testament models) followed after this. Now, what are we to make of this history?
First, the absence of evidence is a tricky thing. That no Christian soldiers are mentioned concretely in existing sources may mean there were none, or it may mean that no occasion arose for the authors of these sources to mention Christians in military service. (There is no discussion of trinitarian doctrine in this period either, but that does not mean early Christians were not trinitarians.) In any case, the hard evidence that there were many Christian soldiers — perhaps the whole body — in a Roman legion in the third quarter of the second century suggests that smaller though significant numbers were present somewhat earlier. The ambiguity of the evidence is illustrated by the fact that Celsus, the pagan critic of Christianity, writing in the last quarter of the second century, asserted (according to Origen’s “Against Celsus”) that Christians did not serve in the army, quite contrary to the evidence of the “Thundering Legion.”
My own thinking is that the early Christians were likely as diverse on the matter of attitudes toward military service as they were on matters of doctrine. It is easy to forget, two millennia later, how slowly doctrinal orthodoxy developed, and how the major positions in every doctrinal controversy rose out of the beliefs and practices of specific groups of Christians. When a given position was laid down as orthodox, it had a history — as did the doctrines labeled heresy. The orthodox position on military service turned out, in the fourth century and later, to be expressed in just war doctrine. It is simply unreasonable to think that this was done without historical roots in Christian belief and practice, without longstanding Christian acceptance of military ser-vice as an allowable livelihood. There is indeed nothing in the skimpy evidence to show otherwise. In short, the best interpretation of early Christian attitudes toward war and peace is that they were as pluralistic as was the early church itself, with military service rejected in some quarters (and, the evidence shows, not always for the same reasons in different quarters) while accepted in others. The roots of just war tradition are thus not in the Constantinian coming together of church and world; they go back much deeper into early Christian history. The “early church” was not “pacifist”; rather, early Christian communities took different stands on military service. Faithfulness to early Christian practice requires at least a willingness to accept similar diversity of conscience today.
One aspect of just war tradition has been the development of an ethic for military behavior, just as one aspect of Christian marriage doctrine has been the definition of proper behavior for Christians in the state of marriage. Augustine contributed to a soldier’s ethic with his idea that just wars required just causes, right authority, a correct intention, and so on, and his use of charity to define limits to even justified violence. Interestingly, in the Middle Ages the church was not at first concerned with an ethic for soldiers; one was contributed initially from chivalric practice and only then consolidated into the church’s position on just warfare. Honore Bonet in the fourteenth century is a useful benchmark: for him soldiering is potentially the highest secular life, but only if it is carried out honorably, with the intent of serving God, and according to the limits of discrimination and proportionality that had by then become established. For him Christian and chivalric ideals were inseparable.
The subsequent evolution of just war thought has moved far from chivalric life, but the ideal of an internalized morality for military service stressing personal honor, to intent of service to God in this worldly calling, and respect for the protection of noncombatants and the common humanity of the enemy remains. For the person in military service as a profession, as for the medieval knight, this ideal serves to define one’s professional, and part of one’s personal, moral identity. For persons in military service for a time, but not for a lifelong calling, this ideal may not be internalized, but even as an external discipline it provides guidance for making sense of Christian life in a military context.