Pope Paul VI
Sacerdotalis Caelibatus §14
Sacerdotalis Caelibatus: On the Celibacy of the Priest
14 Hence We consider that the present law of celibacy should today continue to be linked to the ecclesiastical ministry. This law should support the minister in his exclusive, definitive and total choice of the unique and supreme love of Christ; it should uphold him in the entire dedication of himself to the public worship of God and to the service of the Church; it should distinguish his state of life both among the faithful and in the world at large.
Source: Sacerdotalis Caelibatus (Vatican.va)