3 Your chief praise is that you have promoted and sedulously continue to foster the union of your churches with this chief of churches and with the Vicar of Christ on earth. Herein, as you rightly confess, is the apex and centre of government, of teaching and of the priesthood; the source of that unity which Christ destined for His Church, and which is one of the most striking notes distinguishing it from all human sects. As We have never failed to exercise with advantage this most salutary office of teaching and government in every nation, so we have never permitted that you or your people should suffer the lack of it. For We have gladly availed Ourselves of every opportunity to testify the constancy of Our solicitude for you and for the interests of religion among you. And Our daily experience obliges Us to confess that We have found your people, through your influence, endowed with perfect docility of mind and alacrity of disposition. Therefore, while the changes and tendencies of nearly all the nations which were Catholic for many centuries give cause for sorrow, the state of your churches, in their flourishing youthfulness, cheers Our heart and fills it with delight. True, you are shown no special favor by the law of the land, but on the other hand your lawgivers are certainly entitled to praise for the fact that they do nothing to restrain you in your just liberty. You must, therefore, and with you the Catholic host behind, make strenuous use of the favorable time for action which is now at your disposal by spreading abroad as far as possible the light of truth against the errors and absurd imaginings of the sects that are springing up.
Source: In Amplissimo (Vatican.va)