Man cannot be exempted from his divinely-imposed obligations toward civil society, and the representatives of authority have the right to coerce him when he refuses without reason to do his duty. Society, on the other hand, cannot defraud man of his God-granted right... Nor can society systematically void these rights by making their use impossible.
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 XINo vicarious charity can substitute for justice which is due as an obligation and is wrongfully denied.
Pope Pius XIJustice requires that to lawfully constituted Authority there be given that respect and obedience which is its due; that the laws which are made shall be in wise conformity with the common good; and that, as a matter of conscience all men shall render obedience to these laws.
Pope Pius XIFor them (the peoples of the Soviet Union) We cherish the warmest paternal affection. We are well aware that not a few of them groan beneath the yoke imposed on them by men who in very large part are strangers to the real interests of the country. We recognize that many others were deceived by fallacious hopes. We blame only the system with its authors and abettors who considered Russia the best field for experimenting with a plan elaborated years ago, and who from there continue to spread it from one of the world to the other.
Pope Pius XITo each, therefore, must be given his own share of goods, and the distribution of created goods, which, as every discerning person knows, is laboring today under the gravest evils due to the huge disparity between the few exceedingly rich and the unnumbered propertyless, must be effectively called back to and brought into conformity with the norms of the common good, that is, social justice.
Pope Pius XI