Hundreds of articles and scores of books have been written in the last 150 years seeking to establish what the early (pre-Constantinian) church thought and did about war and killing. Four recent books reflect the ongoing persistent disagreement about the answer to that question.

Two of these books—John F. Shean's Soldiering for God: Christianity and the Roman Army and Despina Iosif's Early Christian Attitudes to War, Violence and Military Service—argue that early Christians held widely divergent views, and that the "rigorist, pacifist stance of selected authors has been overly emphasized at the expense of archaeological, epigraphic and literary evidence showing Christian participation in the military almost since the very inception of the faith."

The other two—George Kalantzis' Caesar and the Lamb: Early Christian Attitudes on War and Military Service and my own book The Early Church on Killing: A Comprehensive Sourcebook on War, Abortion and Capital Punishment—argue that the historical record contradicts the view that the teaching of the early church on killing was "small, divided and ambiguous."

Shean's Soldiering for God is volume 61 of an important series, The History of Warfare, from Brill, a prominent scholarly publisher. Shean argues that there never was unified Christian opposition to Christian participation in the Roman army, even in the first three centuries. "Taken as a body, the writings of the early church fathers do not reflect any consensus on the issue of war and military service." Rather, Shean argues, after exploring the relevant literature, "there was widespread disagreement among the patristic authors over the propriety of Christian participation in Roman military service."

Iosif's Early Christian Attitudes to War, Violence and Military Service is volume 1 in a series on classical and late antiquity from Gorgias Press, a fairly new publishing house. Iosif largely agrees with Shean. Citing inscriptions from tombstones of Christians serving in the Roman army, the use of military metaphors by many Christian writers, and literary references to Christians in the army, Iosif argues that from the earliest period onward, "military careers were not regarded as scandalous, at least not by the majority of Christians." "My aim," she says, "is to refute the well-established notion that all the early Christians were pacifists."

Iosif and Shean's conclusion is shared by many prominent contemporary Christian thinkers in the Just War tradition. See for example James Turner Johnson, The Quest of Peace (Princeton Univ. Press, 1987); Peter J Leithart, Defending Constantine (IVP, 2010); and J. Daryl Charles, Between Pacifism and Jihad. In Just War Against Terror (Basic Books, 2002), Jean Bethke Elshtain (speaking of the first three centuries) maintained that "in these first generations of Christian life after the crucifixion of Jesus, there is little evidence that the faithful were enjoined from serving in the Roman army." Leithart suggests that Tertullian and Origen may have been a small articulate minority, not representative of the majority of Christians.

The thesis of George Kalantzis' Caesar and the Lamb (published by Cascade Books) is quite different. He acknowledges that there is clear evidence for a growing number of Christians in the army in the later 3rd and early 4th centuries, but quotes a number of Christian writers who condemn killing and military service by Christians. He frequently asserts that contrary claims are not supported by the extant sources.

Is there sufficient evidence to resolve this debate one way or the other? In spite of the massive amount of articles and books written about the early Christians' views on war and killing, no scholar had ever collected in one volume all the extant data (literary and archaeological) on the topic. I did that in The Early Church on Killing, published by Baker Academic. This sourcebook contains every extant statement I could find by Christian authors up to the time of Constantine relating directly to killing. It also includes all relevant inscriptions on tombstones and other archaeological data.

In an afterword, I summarize the historical record. Starting in the late 2nd century and then increasingly in the later 3rd century and the first decade of the 4th century, there is evidence that some Christians were serving in the Roman army—at least a few by AD 173, and a substantial number by the late 3rd and early 4th centuries. Unfortunately, our sources do not enable us to say how many.

On the other hand, there is not a single extant Christian author before Constantine who says killing or joining the military by Christians is ever legitimate. Whenever our extant texts mention killing—whether in abortion, capital punishment, or war—they always say Christians must not do that.

There are a substantial number of passages written over a period of many years that explicitly say that Christians must not and/or do not kill or join the military. Nine different Christian writers in 16 different treatises explicitly say that killing is wrong. Four writers in 5 treatises clearly argue that Christians do not and should not join the military. In addition, four writers in eight different works strongly imply that Christians should not join the military. At least eight times, five different authors apply the messianic prophecy about swords being beaten into ploughshares (Isa. 2:4) to Christ and his teaching. Ten different authors in at least 28 different places cite or allude to Jesus' teaching to love enemies, and, in at least nine of these places, they connect that teaching to some statement about Christians being peaceful, ignorant of war, opposed to attacking others, and so forth. All of this represents a considerable consensus.

Indeed, there is very little basis in the texts for describing the early Christian view as "divided and ambiguous." There are no authors who argue that killing or joining the military is permissible for Christians. On these questions, every writer who mentions the subject takes essentially the same position. Some pre-Constantinian Christian writers say more about these topics than others. Some do not discuss them at all. But to conclude from this relative silence or paucity of some surviving texts that other writers disagreed with the extant texts would be sheer speculation. The texts we have do not reflect any substantial disagreement. Every extant Christian statement on killing and war up until the time of Constantine says Christians must not kill, even in war.

That a growing number of Christians, especially in the late 3rd and early 4th centuries, acted contrary to that teaching is also clear. That in doing so they were following other Christian teachers and leaders who justified their conduct, we cannot deny with absolute certainty. But we have no evidence to support the suggestion that such teachers ever existed until the time of Constantine.

So why do scholars like Shean and Iosif argue that the teaching of the early church was divided and ambiguous? To answer that question, one must carefully examine their detailed arguments and interpretations of specific passages.

Shean argues that three of the most important Christian authors of the 3d century (St. Cyprian of Carthage, Clement of Alexandria, and Origen) were "ambivalent" and "did not explicitly object to military service for Christians." His only justification for such an argument in the case of Origen is that Origen prayed for the safety of the Roman Empire and those "fighting in a righteous cause." Origen argued that Christians, like pagan Roman priests, should be exempt from the Roman army since they also prayed for its success (Shean, 101; Contra Celsum, 8.73). But that statement comes in the middle of Origen's long, multi-book response to Celsus, a pagan Roman who had written about AD 180 that since Christians refuse to join the Roman army, the empire would collapse if everyone became a Christian. Repeatedly, in his long response, Origen says Christians love their enemies, do not take vengeance and do not go to war (e.g., Contra Celsum, 2.30; 3.8; 5.33; 7.26; 8.35; 8.73). Christ forbade the killing of anyone (3.7). War would end if all Romans became Christians (8.70). Christians, like the pagan priests who are exempt from military service, must keep their hands "unstained and free from human blood" (8.73). Text after text in Origen contradicts Shean's statement that Origen "did not explicitly object to military service."

No more convincing is Shean's statement that Cyprian and Clement were ambivalent because they used military metaphors. Both Shean and Iosif (as well as others) have argued that the frequent use of military metaphors for the Christian life suggests that the early Christians were not opposed to serving in the military. The problem with this argument is that even the most adamant Christian opponents of killing of any kind (e.g., Lactantius in his Divine Institutes) use military metaphors to describe the Christian's battle against sin and the devil. Cyprian used many military metaphors, but he said manslaughter is a mortal sin, insisted that Christians must not kill, and deplored killing of persons in both war and gladiatorial contests. Nowhere in any of the pre-Constantinian Christian authors have I found any evidence that the use of military metaphors suggested acceptance of Christians joining the army.

In their attempt to downplay the extent of pacifist thought and practice in the early church, both Shean and Iosif substantially overlook the importance of the earliest church order, the Apostolic Tradition. Shean seems to think it was written by Hippolytus, bishop of Rome. Shean says, "Hippolytus' canons had no force outside of his own see … . Indeed it is not clear if Hippolytus' canons were even followed by his successors." Iosif speculates that "we do not know whether these regulations were ever followed or even accepted and authorized as generally binding by the Christian congregation in which their author belonged." But modern scholarship points to a much wider influence; see the understanding of modern scholarship in Paul Bradshaw et al., The Apostolic Tradition (Fortress, 2002). Originally written in Greek (probably in the late 2nd or early 3rd century) it was translated into Sahidic (a Coptic dialect), Arabic, Ethiopic, and Latin. Later church orders written after the time of Constantine incorporate major portions of The Apostolic Tradition but modify its sharp rejection of killing and prohibition of Christians joining the army.

The Apostolic Tradition provides directions for how to deal with people seeking to become catechumens and prepare for baptism. Pimps, prostitutes, gladiators, and anyone who has "the power of the sword" must be rejected. A soldier who wants to begin catechetical training must be told not to kill and must refuse to kill if ordered to do so. A soldier who acts otherwise must be excluded. Someone who is already a Christian and who seeks to join the military must be excluded from the church.

The several translations of The Apostolic Tradition indicate a substantial circulation and impact. To suggest that it only had influence in one diocese for the brief period of one bishop's episcopate is to vastly downplay its significance.[1] The historian would like more information about The Apostolic Tradition's circulation and influence, but it is a reasonable inference from what we do know that it is one of our best clues about the teaching of many Christian leaders in the early 3rd century.

In spite of Tertullian's repeated, vigorous condemnation of Christians serving in the army, Shean claims that Tertullian was ambivalent. Shean even says that "Tertullian saw no problem with Christians engaging in all forms of public service, including armed conflict." The only textual justification for this claim is two very brief statements in his Apology written about AD 197 and addressed to a pagan Roman audience to counter the attacks against Christians. Tertullian wanted to assure Romans that Christians were not a threat to the empire. In his Apology, Tertullian says Christians are engaged in all aspects of ordinary Roman life: "We sail with you, and fight with you." He claims Christians have "filled every place among you—cities, islands, fortresses, towns, market-places, the very camp."

Second, again and again, in all periods of his life, in a number of treatises, Tertullian argued that Christians dare not kill and must not join the Roman army. Christ, he wrote, "unbelted every soldier" (On Idolatry, p. 19). Tertullian's two statements in his Apology clearly show that he knew that there were some Christians in the Roman army in his day. But again and again his writings make it clear that he thought Christians should not join the army or kill. And he encouraged soldiers who became Christians while already in the army to abandon military service. Shean himself acknowledges Tertullian's strong opposition to Christians' service in the army but then tries to dismiss its significance by labeling it a minority opinion: "Tertullian's rigorist ideas probably represented the minority position within the Christian church as his views were also at odds with those of his fellow apologists who saw no moral difficulty in military service." But Shean provides no supporting data for this statement that other Christian writers were not opposed to Christians joining the army.

Another argument that Shean develops for his view that soldiers were a regular and essentially non-controversial part of the Christian community in the first two centuries is based on his claim that "early Christianity would have borne little superficial distinction from any other community of believers in the Mediterranean world." Since soldiers were a central part of 1st- and 2nd-century life in the Roman Empire and Christians were not much different from anyone else, therefore there must have been lots of soldiers in the church. This basic understanding of early Christians as appearing hardly any different from the rest of Roman society is itself highly questionable. But even if it were correct, the inference that therefore there were large numbers of soldiers in the church is an argument from silence. The fact that when we do get Christian authors discussing killing and joining the army, all extant authors condemn such action certainly makes Shean's argument dubious.

As for the later period of the early church, inscriptions on tombstones demonstrate that there were some Christians in the Roman army. But both Shean and Iosif tend to overstate what the data indicate. Iosif says the number of inscriptions is "astonishingly large," and Shean speaks of "plenty" of inscriptional examples confirming the presence of hundreds of Christian men in the Roman army through the 3rd and 4th centuries.

But we dare not lump the 3rd and 4th centuries together if the question is evidence of pre-Constantinian Christian soldiers. Shean himself acknowledges that "the inscriptional evidence for Christian soldiers prior to Constantine is meager." In fact, he notes that in the major collection of these inscriptions, only eight can be clearly dated to be pre-Constantinian. In my research, I identified eleven pre-Constantinian epitaphs that clearly speak of Christian soldiers.

The stories of military martyrs (Christian soldiers who were martyred for their faith) also demonstrate the presence of growing numbers of Christians in the army in the later 3rd century. Many of the stories of military martyrs are more imaginative fiction than historical fact. But historians generally accept the basic historicity of the stories of Marinus (AD 260) and then several others in the last decade of the 3rd century and the early years of the 4th century. But again, Shean makes claims that go beyond the evidence when he says that "it is clear that by the time Maximilian [martyred in 295 for refusing to join the army] was inducted that Christians serving in the army had been a commonplace and that few Christians had any qualms about participating in military life."[2] That an increasing number of Christians were in the army by 295 is clear. But to claim that few Christians had any qualms about joining the army simply goes beyond the evidence we have. In fact, the extant Christian authors—Arnobius of Sicca and Lactantius—whose works date from this period and who mention killing and warfare say clearly that Christians do not do that.

Iosif basically agrees with Shean and develops some additional arguments. She suggests that since "most of the early Christian literary creations lack any discussion on the issue of the legitimacy of war and military service," we should conclude that most Christians in the first three centuries had no problems with joining the Roman army. She cites the fact that the Epistle of Barnabas and the Didache do not discuss the topic of war and concludes that these late 1st- or early 2nd-century Christian writers "were equally unconcerned about Christians entering the Roman army." But this argument from silence proves nothing. One could just as well argue that these writers simply assumed that Christians knew they should not join the army and therefore did not need to discuss the topic.

What the careful historian must do is deal with the evidence we do have. It is true that we do not have a large number of treatises on the topic of how Christians should act with regard to war and killing. But we do have a number of statements by many authors, including a full treatise by Tertullian and many chapters in Contra Celsum by Origen. The relevant data take over one hundred pages to present. And every extant writing by every Christian writer before Constantine who discusses the topic says Christians do not kill or join the army.

Another argument by Iosif is that when the early Christians speak of loving enemies and not being trained in war, they were not talking about public life: "The early Christian Fathers were only explicitly fervent against unnecessary violence among individuals, violence incited by private initiative. There is nothing to prove that these comments reveal a disapproval or aversion of Christian participation in armies and wars."

The data flatly contradict this argument. Lactantius mocks the Roman idea of a just war and condemns every kind of killing, not just the kind of violence prohibited by Roman law but killing in warfare. Those who love their enemies are "ignorant of wars," he writes. Justin Martyr relates Jesus' call to love enemies to the fact that people who formerly were "filled with war and mutual slaughter" now as Christian have changed their swords into ploughshares. Tertullian cites Christ's command to love enemies and declares that God "puts his prohibition on every sort of man-killing."

Iosif and Shean both fail to appreciate the full significance of Origen's insistence, in Contra Celsum, that Christians should not join the Roman army. Origen was probably the most widely read Christian writer of the first half of the 3rd century. A friend and patron of Origen paid for more than a dozen people to write and recopy his flood of writings—contributing greatly to Origen's becoming one of the best-known Christian thinkers of the first half of the 3rd century. As we've already noted, in Contra Celsum Origen refutes the pagan Celsus' charge that if all Romans followed the Christian example of rejecting public office and military service, the Roman Empire would collapse.

Origen's response, in the middle of the 3rd century, was to simply agree with Celsus that Christians do not (and should not) kill or join the army—and then to explain why that is not a problem. In fact, he claims that if all Romans became Christians, war would cease (Contra Celsum, 8.70). If the argument of Shean and Iosif were correct—that most Christians had no problem with military service and that large numbers were serving in the Roman army—then Origen's obvious response would have been to correct Celsus' view that Christians reject military service. But Origen does nothing of the sort. Instead, he matter-of-factly accepts as accurate Celsus' view.

Iosif uses one passage in Clement of Alexandria's Exhortation to argue that this leader of the famous Christian school in Alexandria in the early 3rd century saw no problem with Christians in the military. Clement says: "Practice farming, we say, if you are a farmer, but while you till your fields, know God. Sail the sea, you who are devoted to navigation, yet call the whilst on the heavenly Pilot. Has knowledge taken hold of you while engaged in military service? Listen to the commander, who orders what is right." Iosif claims that Clement is advising the soldier who becomes a Christian to obey his military commander, thus showing that Clement saw no problem with Christians in the army. But there are two flaws in this interpretation. Clement explicitly tells the farmer and sailor who are Christians to continue as they are. But in the third case, that of the soldier who becomes a Christian, Clement does not say to continue as a soldier. Instead, he says obey the commander. Who is the commander? In the previous two cases (farmer and sailor), Clement ends the section with a command to focus on God. It is therefore likely that Clement does the same in the case of the soldier. The commander who is to be listened to is therefore probably Christ. In another text, Clement speaks of Christ as the general who guides his soldiers. We should probably understand this passage along the same lines as The Apostolic Tradition, which says that a soldier who seeks to prepare for baptism must be told not to kill. It is true that Clement says very little about military service. But a number of passages stress the peaceful nature of Christians. And there is no text in Clement that says it is legitimate for Christians to kill or join the army.

One final argument of Shean (and many other modern writers) merits special consideration. Shean points out that the Roman army had enormous power in 3rd- and 4th-century Roman society, even deposing emperors it disliked. Even the strongest Roman emperors had to take account of the thinking of their soldiers. Constantine would not have placed Christian symbols on the shields of his soldiers before the crucial battle at Milvian Bridge in 312 if there had not been a significant number of Christian soldiers in his army. The fact that Christians quickly embraced Constantine, the military conqueror, and rejoiced in his military victories suggests, it is claimed, that opposition to Christians being soldiers had not been widespread in Christian circles.

Several things are important here. First, it is certainly clear from a variety of sources that a growing number of Christians were serving in the Roman army by the late 3rd century. By the first decade of the 4th century, the number of Christian soldiers was substantial.

Second, it is indeed unlikely that Constantine would have embraced Christian symbols in 312 or declared Christianity a legal religion in 313 if there had not been significant numbers of Christians in his army.[3]

Third, the question of what Christian writers and teachers were saying about Christians joining the army is a different question from what some Christians actually did. Over the centuries, Christians have often ignored or disobeyed what their leaders taught. To argue that because Constantine thought it politically wise to adopt Christian symbols in 312, therefore Christian teachers must have been teaching that military service was acceptable for Christians is simply to ignore the historical data.

Furthermore, we have the clear, striking case of Lactantius, who clearly changed his mind after he joined Constantine. His Divine Institutes (started about 304 in the midst of Diocletian's persecution and while Lactantius served as a prominent professor of Latin rhetoric in Nicomedia, where the emperor lived) vigorously condemn every kind of killing (including capital punishment) and reject Christian participation in the army. But by 310, Lactantius has joined Constantine and is tutoring Constantine's son. In On the Death of the Persecutors (c. 313-315), Lactantius celebrates Constantine's military victories. And in later works, Lactantius omits any condemnation of warfare and defends rather than condemns capital punishment.

The case of Lactantius shows not that since Christians embraced and defended Constantine's military victories, they must therefore have not previously thought that killing in war was wrong. Rather, the story of Lactantius demonstrates that one of the most vigorous, uncompromising Christian teachers rejecting all killing in his writing before the time of Constantine could quickly change his views about Christians and killing after experiencing the astonishing end of persecution and embrace of Christianity by Constantine. The case of Lactantius challenges the argument that since Christians quickly celebrated Constantine's military victories, there must not have been much earlier widespread Christian teaching against Christians being soldiers.[4]

The extant historical data make two things perfectly clear. First, as early as 173, there were at least a few Christians in the Roman army. By the late 3rd and early 4th centuries, their numbers were growing substantially, although we lack the data to say how many there were. And second, every single extant pre-Constantinian document by Christian authors that discusses the topic of whether Christians dare ever kill or join the army says no. Shean and Iosif have not produced any evidence to the contrary. As a result, their effort to show that only a few "rigorist" teachers in the pre-Constantinian church were opposed to all killing is based on speculation, not historical data.

Books Discussed In This Essay:

Caesar and the Lamb: Early Christian Attitudes on War and Military Service. George Kalantzis (Cascade Books, 2012).

Early Christian Attitudes to War, Violence and Military Service. Despina Iosif (Gorgias Press, 2013).

Soldiering for God: Christianity and the Roman Army. John F. Shean (Brill, 2010).

Ronald J. Sider is Distinguished Professor of Theology, Holistic Ministry, and Public Policy at Palmer Theological Seminary of Eastern University. He is the author of The Early Church on Killing: A Comprehensive Sourcebook on War, Abortion and Capital Punishment (Baker Academic).

1. Cf. Shean's statement: "There is no evidence, besides The Apostolic Tradition of Hippolytus in the third century, of any attempt on the part of any Christian groups to exclude people solely on the basis of their profession." Cf. also p. 142, where Shean again incorrectly interprets The Apostolic Tradition as representing the views of one individual whose views run contrary to those of most Christians.

2. Cf. Iosif's sweeping statement on military martyrs: "It seems as if only a few Christians ever felt uncomfortable with the military profession" (Iosif, p. 281-2). The data simply do not warrant that kind of sweeping generalization.

3. On the other hand, the fact that Diocletian unleashed the most widespread persecution of Christians starting in 299 raises the opposite question: would he have done that if his army included large numbers of Christians? It is clear from the fact that Diocletian's persecution of Christians started in his army that Christian soldiers were present there. But would he have risked persecuting Christians if a major portion of his army had been Christian?

4. I do, however, think that we need more thorough examination of all the relevant 4th- and 5th-century data to see to what extent (if at all) Christian writers in these centuries still wrestled with the clear rejection of all killing by pre-Constantinian Christian writers.

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