Pope Paul VI
Sacerdotalis Caelibatus §90
Sacerdotalis Caelibatus: On the Celibacy of the Priest
90 Finally, and with deep joy, We thank our Lord because many priests who for a time had been unfaithful to their obligations have again, with the grace of the High Priest, found the path and given joy to all by becoming anew exemplary pastors. With admirable good will, they used all the means which were helpful to ensure their return, especially an intense life of prayer, humility, persevering effort sustained by regular reception of the Sacrament of Penance.
Source: Sacerdotalis Caelibatus (Vatican.va)