Whether considered as a doctrine, or as an historical fact, or as a movemement, socialism, if it really remains socialism, cannotbe brought into harmony with the dogmas of the Catholic church.... Religious socialism, Christian socialism, are expressions implying a contradiction in terms.
Pope Pius XIMen will see in their king or in their rulers men like themselves perhaps unworthy or open to criticism, but they will not on that account refuse obedience if they see reflected in them the authority of Christ, God and Man. Peace and harmony, too, will result; for with the spread and the universal extension of the kingdom of Christ, men will become more and more conscious of the link that binds them together, and thus many conflicts will either be prevented entirely or at least their bitterness be diminished.
Pope Pius XIFor what will it profit men that a more prudent distribution and use of riches make it possible for them to gain even the whole world, if thereby they suffer the loss of their own souls? What will it profit to teach them sound principles in economics, if they permit themselves to be so swept away by selfishness, by unbridled and sordid greed, that hearing the commandments of the Lord, they do all things contrary.
Pope Pius XIFrom it (the Rosary) the young will draw fresh energy with which to control the rebellious tendencies to evil and to preserve intact the stainless purity of the soul. Also in it, the old will again find repose, relief, and peace from their anxious cares. And to all those who suffer in any way, especially the dying, may it bring comfort and increase the hope of eternal happiness.
Pope Pius XIChrist's commandment to hear the Church . . . is binding on all men, in every period, and every country.
Pope Pius XI