Pope Paul VI
Sacerdotalis Caelibatus §68
Sacerdotalis Caelibatus: On the Celibacy of the Priest
68 The exercise of authority, the principle of which should be maintained firmly, will be animated by wise moderation and a pastoral attitude. It will be used in a climate of dialogue and will be implemented in a gradual way which will afford the educator an ever deepening understanding of the psychology of the young man, and will appeal to personal conviction.
Source: Sacerdotalis Caelibatus (Vatican.va)