22 Furthermore, after the terrible war, when the statesmen of the leading nations were attempting to restore peace on the basis of a thorough reform of social conditions, did not they, among the norms agreed upon to regulate in accordance with justice and equity the labor of the workers, give sanction to many points that so remarkably coincide with Leo's principles and instructions as to seem consciously taken therefrom? The Encyclical On the Condition of Workers , without question, has become a memorable document and rightly to it may be applied the words of Isaias: "He shall set up a standard to the nations."
Source: Quadragesimo Anno (Vatican.va)