It is furthermore the duty of the State to ensure that terms of employment are regulated in accordance with justice and equity, and to safeguard the human dignity of workers by making sure that they are not required to work in an environment which may prove harmful to their material and spiritual interests. It was for this reason that the Leonine encyclical enunciated those general principles of rightness and equity which have been assimilated into the social legislation of many a modern State, and which, as Pope Pius XI declared in the encyclical Quadragesimo Anno, 8Cf. AAS 23 (1931) 185. have made no small contribution to the rise and development of that new branch of jurisprudence called labor law.
Pope Leo XIII also defended the worker's natural right to enter into association with his fellows. Such associations may consist either of workers alone or of workers and employers, and should be structured in a way best calculated to safeguard the workers' legitimate professional interest. And it is the natural right of the workers to work without hindrance, freely, and on their own initiative within these associations for the achievement of these ends. Human Solidarity and Christian Brotherhood
Finally, both workers and employers should regulate their mutual relations in accordance with the principle of human solidarity and Christian brotherhood. Unrestricted competition in the liberal sense, and the Marxist creed of class warfare; are clearly contrary to Christian teaching and the nature of man.
These, Venerable Brethren, are the basic principles upon which a genuine social and economic order must be built.
The response of good Catholics to this appeal and the enterprise they showed in reducing these principles into practice is hardly surprising. But others too, men of good will from every nation in the world, were impelled, under pressure of human necessity, to pursue the same course.