7 Therefore, to the Mexican priests, who have dedicated their lives to the service of Jesus Christ, of the Church and of souls - to these We direct Our first and warmest appeal, that they will generously second Our and your solicitude for the progress of Catholic-Action, dedicating to it their best efforts and most opportune diligence. The methods of an effective collaboration of the laity with your action will never be lacking if the priests will devote themselves with careful attention to cultivating the Christian people by means of wise spiritual direction and careful religious instructions, not diluted in vain discourses, but nourished with sound doctrine taken from Holy Scripture and full of unction and of force.
Source: Firmissimam Constantiam (Vatican.va)