44 However, it is necessary—and We can never warn sufficiently of this—that this form of apostolate be carefully adapted to local conditions and needs. What has been done in one country cannot be carried over indiscriminately to another. The people concerned, submitting in all things to the directives of the ecclesiastical hierarchy and willingly obeying their pastors, must beware of defeating the purposes of the apostolate by carrying the burden of an excessive number of activities. For thus they thwart valuable efforts and dissipate valuable energy through compartmentalized and overly specialized projects, which, while satisfactory elsewhere, may be less useful where different conditions and needs prevail. In Our first encyclical, We also promised to deal with the subject of Catholic Action in more detail and at greater length; when We do, We trust that the mission territories will receive additional support and a new incentive. In the meantime, let everyone work in perfect harmony and with supernatural inspiration, in the certainty that only thus will they be able to say that they are serving the divine cause and the common good of their people.
Source: Princeps Pastorum (Vatican.va)