40 All this, though so reasonable and full of counsel, finds little favour nowadays when States not only refuse to conform to the rules of Christian wisdom, but seem even anxious to recede from them further and further on each successive day. Nevertheless, since truth when brought to light is wont, of its own nature, to spread itself far and wide, and gradually take possession of the minds of men, We, moved by the great and holy duty of Our apostolic mission to all nations, speak, as We are bound to do, with freedom. Our eyes are not closed to the spirit of the times. We repudiate not the assured and useful improvements of our age, but devoutly wish affairs of State to take a safer course than they are now taking, and to rest on a more firm foundation without injury to the true freedom of the people; for the best parent and guardian of liberty amongst men is truth. "The truth shall make you free."(25)
Source: Immortale Dei (Vatican.va)