5 In congratulating you on this praiseworthy initiative which is already becoming a consoling reality, We again express Our gratitude to all those who have so generously tendered you hospitality and assistance. And with paternal instinct We remind you again on this occasion of Our precise wish that you make known and explain suitably, not only to the clerics, but to all your priests, Our Encyclical Ad Catholici Sacerdotii , which explains Our thoughts on this the gravest and most important among the grave and important subjects treated by Us.
Source: Firmissimam Constantiam (Vatican.va)