Pope Paul VI
Sacerdotalis Caelibatus §86
Sacerdotalis Caelibatus: On the Celibacy of the Priest
86 If these priests knew how much sorrow, dishonor and unrest they bring to the holy Church of God, if they reflected on the seriousness and beauty of their obligations and on the dangers to which they are exposed in this life and in the next, there would be greater care and reflection in their decisions; they would pray more assiduously and show greater courage and logic in forestalling the causes of their spiritual and moral collapse.
Source: Sacerdotalis Caelibatus (Vatican.va)