If Socialism, like all errors, contains some truth (which, moreover, the Supreme Pontiffs have never denied), it is based nevertheless on a theory of human society peculiar to itself and irreconcilable with true Christianity. Religious socialism, Christian socialism, are contradictory terms; no one can be at the same time a good Catholic and a true socialist.
Pope Pius XIIn his laborious efforts to attain mountaintops, where the air is lighter and purer, the climber gains new strength of limb. In the endeavor to over come obstacles of the way, the soul trains itself to conquer difficulties; and the spectacle of the vast horizon, which from the highest crest offers itself on all sides to the eyes, raises his spirit to the Divine Author and Soverign of Nature.
Pope Pius XIAlways moved by religious motives, the Church has condemned the various forms of Marxist Socialism; and she condemns them today, because it is her permanent right and duty to safeguard men from currents of thought and influence that jeopardize their eternal salvation.
Pope Pius XIChrist's commandment to hear the Church . . . is binding on all men, in every period, and every country.
Pope Pius XIIt is not enough to be a member of the Church of Christ, one needs to be a living member, in spirit and in truth, i.e., living in the state of grace and in the presence of God, either in innocence or in sincere repentance.
Pope Pius XIHowever we may pity the mother whose health and even life is imperiled by the performance of her natural duty, there yet remains no sufficient reason for condoning the direct murder of the innocent.
Pope Pius XIFor they have always unanimously maintained that nature, rather the Creator Himself, has given man the right of private ownership not only that individuals may be able to provide for themselves and their families but also that the goods which the Creator destined for the entire family of mankind may through this institution truly serve this purpose.
Pope Pius XI