Pope Paul VI
Sacerdotalis Caelibatus §46
Sacerdotalis Caelibatus: On the Celibacy of the Priest
46 Yes, venerable and well-beloved brothers in the priesthood, whom We cherish "with the affection of Christ Jesus," (90) it is indeed this world in which we live, tormented by the pains of growth and change, justly proud of its human values and human conquests, which urgently needs the witness of lives consecrated to the highest and most sacred spiritual values. This witness is necessary in order that the rare and incomparable light radiating from the most sublime virtues of the spirit may not be wanting to our times.
Source: Sacerdotalis Caelibatus (Vatican.va)