Pope Paul VI
Sacerdotalis Caelibatus §81
Sacerdotalis Caelibatus: On the Celibacy of the Priest
81 Priests should reflect on the advice of the Council, (134) which reminds them of their common sharing in the priesthood so that they may feel a lively responsibility for fellow priests troubled by difficulties which gravely endanger the divine gift they have. They should have a burning charity for those who have greater need of love, understanding and prayer, who have need of prudent but effective help, and who have a claim on their unbounded charity as those who are, and should be, their truest friends.
Source: Sacerdotalis Caelibatus (Vatican.va)