25 Consider the truths themselves which the priest if faithful to his ministry, must frequently inculcate. Ponder them one by one and dwell upon their inner power; for they make plain the influence of the priest, and how strong and beneficent it can be for the moral education, social concord and peaceful development of peoples. He brings home to young and old the fleeting nature of the present life; the perishableness of earthly goods; the value of spiritual goods and of the immortal soul; the severity of divine judgment; the spotless holiness of the divine gaze that reads the hearts of all; the justice of God, which "will render to every man according to his works." These and similar lessons the priest teaches; a teaching fitted indeed to moderate the feverish search for pleasure, and the uncontrolled greed for worldly goods, that debase so much of modern life, and spur on the different classes of society to fight one another like enemies, instead of helping one another like friends. In this clash of selfish interest, and unleashed hate, and dark plans of revenge, nothing could be better or more powerful to help, than loudly to proclaim the "new commandment" of Christ. That commandment enjoins a love which extends to all, knows no barriers nor national boundaries, excludes no race, excepts not even its own enemies.
Source: Ad Catholici Sacerdotii (Vatican.va)