11 Since a problem was being treated "for which no satisfactory solution" is found "unless religion and the Church have been called upon to aid," the Pope, clearly exercising his right and correctly holding that the guardianship of religion and the stewardship over those things that are closely bound up with it had been entrusted especially to him and relying solely upon the unchangeable principles drawn from the treasury of right reason and Divine Revelation, confidently and as one having authority, declared and proclaimed "the rights and duties within which the rich and the proletariat - those who furnish material things and those who furnish work - ought to be restricted in relation to each other," and what the Church, heads of States and the people themselves directly concerned ought to do.
Source: Quadragesimo Anno (Vatican.va)