Augustine

Until the conversion of Constantine in 324 AD Christians were invariably pacifist. Theologians of this period, such as Tertullian (160-220) or Origen (185-254) seemed to assume that all killing was contrary to the law of Christ. Origen was accused by some of undermining the state through his pacifism. He answered:

“None fight better for the King than we do. We do not indeed fight under him, although he require it; but we fight on his behalf, forming a special army, an army of piety, by offering our prayers to God” (Against Celsius 8.73).

When Christianity became the state religion there needed to be a moral justification for a standing army, and a moral case for war when faced with the threat of barbarian invasion.

Augustine (354-430) provided such a justification. He saw Peter’s use of the sword in the garden as an example of “hasty zeal” without authority, rather than condemnation of the sword as such. He argued that Jesus never taught openly about war or condemned the centurion for his occupation: he tried to reconcile the Old and New Testament positions, rather than arguing (as Tertullian had) that Jesus revokes it.

Augustine took a deontological approach, arguing that war was justified, because God commanded it in the Old Testament (in such passages as Joshua 10:40 or Deuteronomy 2:34). He argued that God alone could sanction such war “because he alone knows the suitable command in every case, and who alone is incapable of inflicting unmerited suffering on anyone” (Reply to Faustus VII.4). In so arguing Augustine is taking a natural law stance, for example in affirming “the act, the agent, and the authority for the action are all of great importance in the order of nature”.

But he also derived from Greek and Roman attitudes to war (such as Cicero’s) the ideas of “lawful authority”, “natural order” and “justice in war”, “for the natural order which seeks the peace of mankind, ordains that the monarch should have the power of undertaking war if he thinks it advisable, and that soldiers should perform their military duties on behalf of the peace and safety of the community” (VII.7).

Few people today would accept Augustine’s view of the morality of war in the Old Testament, which seems at best to be precritical and at worst imputing immoral actions to God. However Augustine first put forward the three criteria developed by Aquinas.