4 Indeed, from these assemblies and exhortations on the part of bishops, Catholics have been inspired to hold and attend similar assemblies on the national, provincial, or local level, an undertaking of the greatest foresight. For, if evil men, strong in numbers and acumen unite here and there and conspire together to treacherously deprive Catholics of the gift of faith and its attendant advantages, surely it is right and necessary that Catholics should utilize their zeal and abilities to resist. In such gatherings, they can more freely and firmly undertake the profession of their faith and repel the enemy attacks upon it.
Source: In Ipso (Vatican.va)