Mater et Magistra §8

⁸ Seldom have the words of a Pontiff met with such universal acclaim. In the weight and scope of his arguments, and in the forcefulness of their expression, Pope Leo XIII can have but few rivals. Beyond any shadow of doubt, his directives and appeals have established for themselves a position of such high importance that they will never, surely, sink into oblivion. They opened out new horizons for the activity of the universal Church, and the Supreme Shepherd, by giving expression to the hardships and sufferings and aspirations of the lowly and oppressed, made himself the champion and restorer of their rights.