Pope Paul VI
Sacerdotalis Caelibatus §79
Sacerdotalis Caelibatus: On the Celibacy of the Priest
79 Moreover, priestly chastity is increased, guarded and defended by a way of life, surroundings and activity suited to a minister of God. For this reason the "close sacramental brotherhood (131) which all priests enjoy in virtue of their ordination must be fostered to the utmost. Our Lord Jesus Christ has taught the urgency of the new commandment of charity. He gave a wonderful example of it when He instituted the sacrament of the Eucharist and the Catholic priesthood, (l32) and prayed to His Heavenly Father that the love the Father bore for Him from all eternity should be in His ministers and that He too should be in them. (133)
Source: Sacerdotalis Caelibatus (Vatican.va)