Thomas Aquinas

“ Even those who seek war and dissension, desire nothing but peace, which they deem themselves not to have. For as we stated above, there is no peace when a man concords with another man counter to what he would prefer. Consequently men seek by means of war to break this concord, because it is a defective peace, in order that they may obtain peace, where nothing is contrary to their will. Hence all wars are waged that men may find a more perfect peace than that which they had heretofore.
Reply to Objection 3: Peace gives calm and unity to the appetite. ”

“ Several vices are opposed to one virtue in respect of its various acts: so that not only is hatred opposed to charity, in respect of its act which is love, but also sloth and envy, in respect of joy, and dissension in respect of peace. ”

“ Augustine is speaking there of that peace which is between one man and another, and he says that this peace is concord, not indeed any kind of concord, but that which is well ordered, through one man agreeing with another in respect of something befitting to both of them . For if one man concord with another, not of his own accord, but through being forced, as it were, by the fear of some evil that besets him, such concord is not really peace, because the order of each concordant is not observed, but is disturbed by some fear-inspiring cause. ”

“ Whether peace is an effect of charity?
(4) Whether peace is a virtue?
Art. 1 - Whether peace is the same as concord? Objection 1: It would seem that peace is the same as concord. For Augustine says (De Civ. Dei xix, 13) : "Peace among men is well ordered concord." Now we are speaking here of no other peace than that of men. Therefore peace is the same as concord.
Objection 2: Further, concord is union of wills. Now the nature of peace consists in such like union, for Dionysius says (Div. Nom. xi) that peace unites all, and makes them of one mind. Therefore peace is the same as concord. ”

“ Secondly, in so far as one and the same appetitive power tends to diverse objects of appetite, which it cannot obtain all at the same time: so that there must needs be a clashing of the movements of the appetite. ”

“ For, though fire by heating, both liquefies and rarefies, there are not two powers in fire, one of liquefaction, the other of rarefaction: and fire produces all such actions by its own power of calefaction. ”