We are good at killing. People have always been good at killing. We spend money and man-hours trying to find better, more efficient ways to end lives. I’m not trying to be political; I just suppose it’s part of our human nature, as this has been our history.
NOTE: I am a religion major and my areas of focus have been theology and the New Testament. In other words, I tend to ramble. I will attempt to be pithy and non-academic, as I sometimes will lose even myself. Sorry about all the footnotes – just trying to be academically honest and true to my sources. A list of my sources will be posted after the final installment.
Developed Just War theory has precursors in pagan societies, including sixth-century B.C.E. Chinese Taoism. Armed conflict was viewed as a “regrettable necessity,” as “violence would be against the Tao, and he who is against the Tao dies young.”  But when, “the use of soldiers cannot be avoided, [the] best policy is calm restraint… The slaying of multitudes should be mourned with sorrow.” In the fourth century B.C.E., the Hindu society codified in the Book of Manu rules for ‘honorable warriors.’ Both Plato and Aristotle recognize war as a necessary evil; yet question what justifies going to war.
However, the Early Christian Church was pacifist. Although not entirely uniform in this view, it was held by a vast majority of early Christians. Early Christian actions reflect this. A strong light can be cast on Early Christians’ attitude to war by the serious view they took of the precepts of Jesus enjoining love for all, including enemies, and forbidding retaliation upon the wrongdoer.
The Early Church’s philosophy of pacifism began to change at the time of Constantine with the merging of church and state. Because of the integration of the church and Roman Imperial State, and also partly due to the threat of barbarian invasions, Christians in the fourth and fifth centuries took over from the classical world the doctrine of the just war.
Early Church fathers, including Tertullian were pacifists as well, strongly discouraging Christians from participating in military service. He viewed service to the state as idolatrous; “One soul cannot be owing to two masters – God and Caesar.” Just War theory as a part of Christianity is developed by the works of Ambrose and then more fully by Augustine (five hundred years removed from the time of Christ). Christian participation in war became easier to accept as is became more closely tied to the protection of the Roman Empire.
And since the time Jesus of Nazareth walked the earth, his followers have taken three views when it comes to war: Pacifism, Just War, and the Crusade. The idea of Just War by Christians was further refined and implemented, and then taken to an extreme (by anyone’s standards) with the start of the Crusades in the eleventh century. Theologians who discussed the ethic of war laid stress not on the protection of life and honor, as Augustine had done, but on the protection of property. The Church’s ties to the polity of the Roman Empire facilitated a compromise from their earlier practices that eventually led to a reasoning many Christians still hold today: under certain circumstances it’s acceptable for Christians to go to war.
I do not trace this history to say that because of an early tradition, Christians should be pacifists. Rather, I have outlined all this in hopes that we can see what the first Christians, those who lived and walked in relatively the same time of Jesus, believed Jesus meant and how closely they believed his commands should be followed.
 So, Sun Tzu, The Art of War 1.1 in War and Peace, 5:301.
 Charles, Between Pacifism and Jihad, 31.
 Lao Tzu, The Wisdom of Lao Tzu, 562-63.
 Charles, Between Pacifism and Jihad, 32.
 Bainton, Christian Attitudes Toward War and Peace, 14.
 Charles, Between Pacifism and Jihad, 33.
 So, Bainton, Christian Attitudes Toward War and Peace, 14.
 Cadoux, The Early Christian Attitude to War, 67.
 Bainton, Christian Attitudes Toward War and Peace, 14; 85
 Tertullian, On Idolatry, 17.
 Ibid., 19.
 Bainton, Christian Attitudes Toward War and Peace, 89.
 Ibid., 90.
 Ibid., 15.
 Ibid., 106.