Rerum Novarum §2

² Therefore, venerable brethren, as on former occasions when it seemed opportune to refute false teaching, We have addressed you in the interests of the Church and of the common weal, and have issued letters bearing on political power, human liberty, the Christian constitution of the State, and like matters, so have We thought it expedient now to speak on the condition of the working classes.(1) It is a subject on which We have already touched more than once, incidentally. But in the present letter, the responsibility of the apostolic office urges Us to treat the question of set purpose and in detail, in order that no misapprehension may exist as to the principles which truth and justice dictate for its settlement. The discussion is not easy, nor is it void of danger. It is no easy matter to define the relative rights and mutual duties of the rich and of the poor, of capital and of labor. And the danger lies in this, that crafty agitators are intent on making use of these differences of opinion to pervert men's judgments and to stir up the people to revolt.