“War may sometimes be a necessary evil. But no matter how necessary, it is always an evil, never a good. We will not learn to live together in peace by killing each other's children. The bond of our common humanity is stronger than the divisiveness of our fears and prejudices. God gives us the capacity for choice. We can choose to alleviate suffering. We can choose to work together for peace. We can make these changes - and we must.”
"My heart is deeply wounded in particular by what is happening in Syria and anguished by the dramatic developments which are looming. I appeal strongly for peace, an appeal which arises from deep within me. How much suffering, how much devastation, how much pain has the use of arms carried in its wake in that martyred country, especially among civilians and the unarmed! I think of many children will not see the light of the future! With utmost firmness I condemn the use of chemical weapons: I tell you that those terrible images from recent days are burned into my mind and heart. There is a judgment of God and of history upon our actions which are inescapable! Never has the use of violence brought peace in its wake. War begets war, violence begets violence."
“The strict conditions for legitimate defense by military force require rigorous consideration. The gravity of such a decision makes it subject to rigorous conditions of moral legitimacy. At one and the same time: - the damage inflicted by the aggressor on the nation or community of nations must be lasting, grave, and certain; - all other means of putting an end to it must have been shown to be impractical or ineffective; - there must be serious prospects of success; - the use of arms must not produce evils and disorders graver than the evil to be eliminated. The power of modern means of destruction weighs very heavily in evaluating this condition. These are the traditional elements enumerated in what is called the ‘just war’ doctrine. The evaluation of these conditions for moral legitimacy belongs to the prudential judgment of those who have responsibility for the common good.” (#2309)
“Justice is a kind of mean, but not in the same way as the other virtues, but because it relates to an intermediate amount, while injustice relates to the extremes. And justice is that in virtue of which the just man is said to be a doer, by choice, of that which is just, and one who will distribute either between himself and another or between two others not so as to give more of what is desirable to himself and less to his neighbor (and conversely with what is harmful), but so as to give what is equal in accordance with proportion; and similarly in distributing between two other persons.”
“And if anyone would reduce [justice] to the proper form of a definition, he might say that ‘justice is a habit whereby a man renders to each one his due by a constant and perpetual will’: and this is about the same definition as that given by the Philosopher (Ethic. v, 5) who says that ‘justice is a habit whereby a man is said to be capable of doing just actions in accordance with his choice.’”
“Peace, we know, is above all a gift from on high which we must ask for with insistence and which, moreover, we must all construct through a profound inner conversion…Respond to blind violence and inhuman hatred with the fascinating power of love. Keep far away from every form of exasperated nationalism, racism and intolerance. Witness with your life that ideas are not imposed but proposed.”