45 In short the very height, or, to use St. Epiphanius' phrase, "the incredible honor and dignity" of the Christian priesthood, which We have briefly described, shows how becoming is clerical celibacy and the law which enjoins it. Priests have a duty which, in a certain way, is higher than that of the most pure spirits "who stand before the Lord." Is it not right, then, that he live an all but angelic life? A priest is one who should be totally dedicated to the things of the Lord. Is it not right, then, that he be entirely detached from the things of the world, and have his conversation in Heaven? A priest's charge is to be solicitous for the eternal salvation of souls, continuing in their regard the work of the Redeemer. Is it not, then, fitting that he keep himself free from the cares of a family, which would absorb a great part of his energies?
Source: Ad Catholici Sacerdotii (Vatican.va)