13 You, Venerable Brethren, understand how much this question is in Our mind, and We desire that Our children should also know, not only those who belong to the Catholic community, but also those who are separated from Us: if these latter humbly beg light from heaven, there is no doubt but that they will recognize the one true Church of Jesus Christ and will, at last, enter it, being united with us in perfect charity. While awaiting this event, and as a pledge of Our paternal good will, We impart most lovingly to you, Venerable Brethren, and to your clergy and people, the apostolic benediction. Given at Rome, at Saint Peter's, on the 6th day of January, on the Feast of the Epiphany of Jesus Christ, our Lord, in the year 1928, and the sixth year of Our Pontificate.
Source: Mortalium Animos (Vatican.va)