Thomas Aquinas

“ I answer that, Several things are requisite for the good of a human society: and a number of things are done better and quicker by a number of persons than by one, as the Philosopher observes (Polit. i, 1) , while certain occupations are so inconsistent with one another, that they cannot be fittingly exercised at the same time; wherefore those who are deputed to important duties are forbidden to occupy themselves with things of small importance. ”

“ And yet even those who make sinful use of the sword are not always slain with the sword, yet they always perish with their own sword, because, unless they repent, they are punished eternally for their sinful use of the sword. ”

“ First, the authority of the sovereign by whose command the war is to be waged. For it is not the business of a private individual to declare war, because he can seek for redress of his rights from the tribunal of his superior. Moreover it is not the business of a private individual to summon together the people, which has to be done in wartime. ”

“ The first reason is a general one, because, to wit, warlike pursuits are full of unrest, so that they hinder the mind very much from the contemplation of Divine things, the praise of God, and prayers for the people, which belong to the duties of a cleric. Wherefore just as commercial enterprises are forbidden to clerics, because they unsettle the mind too much, so too are warlike pursuits, according to 2 Tim. 2:4: "No man being a soldier to God, entangleth himself with secular business." ”

“ Now, among the faithful, carnal wars should be considered as having for their end the Divine spiritual good to which clerics are deputed. Wherefore it is the duty of clerics to dispose and counsel other men to engage in just wars. For they are forbidden to take up arms, not as though it were a sin, but because such an occupation is unbecoming their personality. ”

“ And as the care of the common weal is committed to those who are in authority, it is their business to watch over the common weal of the city, kingdom or province subject to them. And just as it is lawful for them to have recourse to the sword in defending that common weal against internal disturbances, when they punish evil-doers, according to the words of the Apostle (Rom. 13:4) : "He beareth not the sword in vain: for he is God's minister, an avenger to execute wrath upon him that doth evil" ”

“ Art. 2 - Whether it is lawful for clerics and bishops to fight? Objection 1: It would seem lawful for clerics and bishops to fight. For, as stated above (A [1] ) , wars are lawful and just in so far as they protect the poor and the entire common weal from suffering at the hands of the foe. Now this seems to be above all the duty of prelates, for Gregory says (Hom. in Ev. xiv) : "The wolf comes upon the sheep, when any unjust and rapacious man oppresses those who are faithful and humble. ”

“ But ambushes, since they are a kind of deception, seem to pertain to injustice. Therefore it is unlawful to lay ambushes even in a just war.
Objection 2: Further, ambushes and deception seem to be opposed to faithfulness even as lies are. But since we are bound to keep faith with all men, it is wrong to lie to anyone, as Augustine states (Contra Mend. xv) . Therefore, as one is bound to keep faith with one's enemy, as Augustine states (Ep. ad Bonif. clxxxix) , it seems that it is unlawful to lay ambushes for one's enemies. ”

“ Further, no ill deed should be done to avoid temporal harm. But fighting on a holy day seems in itself to be an ill deed. Therefore no one should fight on a holy day even through the need of avoiding temporal harm. ”

“ Secondly, a man may be deceived by what we say or do, because we do not declare our purpose or meaning to him. Now we are not always bound to do this, since even in the Sacred Doctrine many things have to be concealed, especially from unbelievers, lest they deride it, according to Mat. 7:6: "Give not that which is holy, to dogs." Wherefore much more ought the plan of campaign to be hidden from the enemy. ”

“ Prelates and clerics may, by the authority of their superiors, take part in wars, not indeed by taking up arms themselves, but by affording spiritual help to those who fight justly, by exhorting and absolving them, and by other like spiritual helps. ”

“ For this reason it has been decreed that those who shed blood, even without sin, become irregular. Now no man who has a certain duty to perform, can lawfully do that which renders him unfit for that duty. Wherefore it is altogether unlawful for clerics to fight, because war is directed to the shedding of blood.
Reply to Objection 1: Prelates ought to withstand not only the wolf who brings spiritual death upon the flock, but also the pillager and the oppressor who work bodily harm ”

“ Wherefore it is unbecoming for them to slay or shed blood, and it is more fitting that they should be ready to shed their own blood for Christ, so as to imitate in deed what they portray in their ministry. ”