From the Quadragesimo Anno, 15 maggio 1931, Pope Pius XI: «In that way, that is, the unity of human society cannot be founded on class opposition, thus the correct order of the economy cannot be abandoned to the free competition of forces. From this end indeed, as if from a poisoned source, all the errors of individualistic economic science are derived, which forgets or ignores that the economy has its own social character, no less than moral, he believed that the public authority should esteem her and leave her absolutely free to her own devices, like that which had to find its own guiding principle or rudder in the market or free competition, according to which it would be directed much more perfectly than for any created intelligence. Except for free competition, although it is certainly fair and useful if contained within well-determined limits; it cannot be the helm of the economy in any way; which is demonstrated all too well by experience, when the norms of the individualistic spirit were applied in practice. It is therefore completely necessary for the economy to return to being regulated according to its true and effective guiding principle. But that office can be taken much less by that economic supremacy, which in recent times has been replacing free competition; so long as, it being a blind force and a violent energy, to become useful to men it needs to be wisely restrained and guided. We must therefore seek higher and more noble principles by which this hegemony can be vigorously and totally governed: and such are social justice and charity. Therefore it is necessary that the institutions of peoples are inspired by social justice, indeed of the entire life of society; and even more so, it is necessary for this justice to be truly effective, that is, it constitutes a legal and social order to which the entire economy conforms.
Social charity must then be like the soul of this order, whose effective protection and enforcement must be ensured by the public authority; and she will be able to do it all the more easily if she frees herself from those burdens that are not her own, as we stated above. That, On the contrary, it is convenient that the various nations, uniting purposes and forces together, since in the economic field they are mutually dependent and must help each other, let them strive to promote successful international economic cooperation with wise conventions and institutions. Therefore, if the members of the social body will be thus strengthened, and its guiding principle as the rudder of the social economy will be straightened, it will be possible to say in some way about the social order what the Apostle says about the mystical body of Jesus Christ: that the whole body is combined and connected thanks to all the communication joints, by virtue of the proportionate operation above each member, takes the increase of the body itself for its perfection through charity (Ef 4, 16). (…) The relationships therefore between one and the other must be regulated according to the laws of a very exact commutative justice, supported by Christian charity. Free competition is necessary, confined within reasonable and just limits, and even more so that economic power is in fact subject to public authority, in what concerns the office of the latter. Finally, the institutions of peoples will have to adapt society as a whole to the needs of the common good, that is, to the laws of social justice; hence it will necessarily follow that such an important section of social life, what is the economic activity, will in turn be brought back to a healthy and well-balanced order. (…) Nor should one therefore believe that those parties or groups of socialists, who are not communists, they all changed their minds to this extent, either in fact or in their program. No, because they mostly, they do not reject the class struggle, nor the abolition of property, but they just want it mitigated in some way. Except, their false principles having thus been mitigated and somehow cancelled, arises from it, or rather it is moved by someone, doubt: if perhaps even the principles of Christian truth cannot be mitigated or tempered in some way, to thus move towards socialism and almost by a middle way come to an agreement together. And there are those who harbor the vain hope of drawing the socialists to us in this way. Vain hope, let's say. Those, Indeed, who want to be apostles among socialists, they must profess openly and sincerely, in its fullness and integrity, Christian truth, and in no way use connivance with errors. That, if they really want to be preachers of the Gospel, they must first of all try to make the socialists see their demands, as they have what is right, they can be supported much more validly with the principles of Christian faith and promoted much more effectively with the forces of Christian charity. (…) However provoked by the insults and pierced in the father's heart, we are far from rejecting these children from Us, although so miserably misguided and far from truth and salvation. Indeed, with all our ardor and with all our liveliest concern we invite them to return to the maternal bosom of the Church. And God grant that they will listen to Our voice! Let them return from where they started, that is, to the house of the Father and there they persevere where their proper place is, among the ranks, that is, of those who followed the teachings of Leo XIII, now solemnly renewed by Us, they study to restore society according to the spirit of the Church, strengthening social justice and charity. And let them be persuaded that they will never be able to find greater happiness elsewhere, even on this earth, if not close to Him who for our love “being rich, he became poor, so that from His poverty we might become rich" (2 Cor., 8, 9), who was poor and struggling from his youth, who invites to himself all those oppressed by fatigue and afflictions to give them full comfort in the charity of his Heart (Mt., 11, 28); and that finally, without accepting people, he will demand more from those to whom he has given more (cfr. Luc., 12, 48), and he will repay everyone according to his work (Mt., 16, 27)».
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