65 The militant leaders of Catholic Action thus properly prepared and armed, will be the first and immediate apostles of their fellow workmen. They will be an invaluable aid to the priest in carrying the torch of truth, and in relieving grave spiritual and material suffering, in many sectors where inveterate anti-clerical prejudice or deplorable religious indifference has proved a constant obstacle to the pastoral activity of God's ministers. In this way they will collaborate, under the direction of especially qualified priests, in that work of spiritual aid to the laboring classes on which We set so much store, because it is the means best calculated to save these, Our beloved children, from the snares of Communism.
Source: Divini Redemptoris (Vatican.va)