61 To priests in a special way We recommend anew the oft-repeated counsel of Our Predecessor, Leo XIII, to go to the workingman. We make this advice Our own, and faithful to the teachings of Jesus Christ and His Church, We thus complete it: "Go to the workingman, especially where he is poor; and in general, go to the poor." The poor are obviously more exposed than others to the wiles of agitators who, taking advantage of their extreme need, kindle their hearts to envy of the rich and urge them to seize by force what fortune seems to have denied them unjustly. If the priest will not go to the workingman and to the poor, to warn them or to disabuse them of prejudice and false theory, they will become an easy prey for the apostles of Communism .
Source: Divini Redemptoris (Vatican.va)