12 And first endeavour to make your people understand of what value the Catholic Faith is to them, and how they ought to defend it at every cost. But, since the enemies and assailants of the Catholic name employ a thousand devices and a thousand feints to seduce those who are not on their guard, it is of the first importance to unmask and drag into the light of day their secret machinations, so that Catholics, having their eyes opened to the real aims of these men, may feel their own courage redoubled, and may resolve openly and intrepidly to defend the Church, the Roman Pontiff, and their own salvation.
Source: Etsi Nos (Vatican.va)