81 What a consolation it is for you, beloved sons, and what a pledge of assured victory to consider that this hidden and peaceful warfare that you are waging for Holy Church is not yours alone or that of your age or your people, but the ever-enduring conflict of the whole Church which it behooves all her children to carry on manfully, since it is their bounden duty to return thanks to God and to their brethren for the gift of faith received in their baptism.
Source: Fidei Donum (Vatican.va)