31 For, as you well know, Venerable Brethren, Our most recent predecessors have often issued serious warnings to priests about the extent of the dangers that are arising among the clergy from a growing carelessness about obedience with regard to the teaching authority of the Church, to the various ways and means of undertaking the apostolate, and to ecclesiastical discipline.
Source: Sacerdotii Nostri Primordia (Vatican.va)