Men 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 XI"Religious Socialism," "Christian Socialism," are expressions implying a contradiction in terms.
Pope Pius XIFurthermore, in this one Church of Christ no man can be or remain who does not accept, recognize and obey the authority and supremacy of Peter and his legitimate successors.
Pope Pius XIChrist's commandment to hear the Church . . . is binding on all men, in every period, and every country.
Pope Pius XI