20 Peace indeed was signed in solemn conclave between the belligerents of the late War. This peace, however, was only written into treaties. It was not received into the hearts of men, who still cherish the desire to fight one another and to continue to menace in a most serious manner the quiet and stability of civil society. Unfortunately the law of violence held sway so long that it has weakened and almost obliterated all traces of those natural feelings of love and mercy which the law of Christian charity has done so much to encourage. Nor has this illusory peace, written only on paper, served as yet to reawaken similar noble sentiments in the souls of men. On the contrary, there has been born a spirit of violence and of hatred which, because it has been indulged in for so long, has become almost second nature in many men. There has followed the blind rule of the inferior parts of the soul over the superior, that rule of the lower elements "fighting against the law of the mind," which St. Paul grieved over. ( Rom . vii, 23)
Source: Ubi Arcano Dei Consilio (Vatican.va)