Quadragesimo Anno §141

¹⁴¹ The present state of affairs, Venerable Brethren, clearly indicates the way in which We ought to proceed. For We are now confronted, as more than once before in the history of the Church, with a world that in large part has almost fallen back into paganism. That these whole classes of men may be brought back to Christ Whom they have denied, we must recruit and train from among them, themselves, auxiliary soldiers of the Church who know them well and their minds and wishes, and can reach their hearts with a tender brotherly love. The first and immediate apostles to the workers ought to be workers; the apostles to those who follow industry and trade ought to be from among them themselves.