16 In a spirit of faith, therefore, We look on this occasion afforded Us by Divine Providence as a favorable opportunity for setting forth anew, and in a way more suited to the men of our time, the fundamental reasons for sacred celibacy. If difficulties against faith "can stimulate our minds to a more accurate and deeper understanding" of it, (9) the same is true of the ecclesiastical discipline which guides and directs the life of the faithful. We are deeply moved by the joy this occasion gives Us of contemplating the richness in virtue and the beauty of the Church of Christ. These may not always be immediately apparent to the human eye, because they derive from the love of the divine Head of the Church and because they are revealed in the perfection of holiness (10) which moves the human spirit to admiration, and which human resources cannot adequately explain.
Source: Sacerdotalis Caelibatus (Vatican.va)