Pope Paul VI
Sacerdotalis Caelibatus §50
Sacerdotalis Caelibatus: On the Celibacy of the Priest
50 As We said above, (99) the Church is not unaware that the choice of consecrated celibacy, since it involves a series of hard renunciations which affect the very depths of a man, presents also grave difficulties and problems to which the men of today are particularly sensitive. In fact, it might seem that celibacy conflicts with the solemn recognition of human values by the Church in the recent Council. And yet more careful consideration reveals that this sacrifice of the human love experienced by most men in family life and given up by the priest for the love of Christ, is really a singular tribute paid to that great love. For it is universally recognized that man has always offered to God that which is worthy of both the giver and the receiver.
Source: Sacerdotalis Caelibatus (Vatican.va)