5 And from this work which We have undertaken for the good of many souls deprived of every consolation of the Catholic religion, We promise the most abundant fruits, especially if, as We trust, We are assisted in its growth by the zeal and assistance of those of the faithful whose means equal their piety. Moreover, We pray to the good God Who wishes all to be saved and to arrive at the knowledge of truth, that He may look graciously upon those beginnings, and may give a successful increase; and We very lovingly grant the Apostolic Blessing as a pledge of Our most devoted affection to you,Venerable Brethren, and to all the Clergy and Faithful whom you rule. Given at Rome at St. Peters, December 10th, 1888. The 11th year of Our Pontificate.
Source: Quam Aerumnosa (Vatican.va)