The priest has as the proper field of his activity everything that pertains to the supernatural life, since it is he who promotes the increase of this supernatural life and communicates it to the Mystical Body of Jesus Christ. Consequently, it is necessary that he renounce "the things of the world," in order to have care only for "the things of the Lord". And it is precisely because he should be free from preoccupation with worldly things to dedicate himself entirely to the divine service, that the Church has established the law of celibacy, thus making it ever more manifest to all peoples that the priest is a minister of God and the father of souls. By his law of celibacy, the priest, so far from losing the gift and duties of fatherhood, rather increases them immeasurably, for, although he does not beget progeny for this passing life of earth, he begets children for that life which is heavenly and eternal. The more resplendent priestly chastity is, so much the more does the sacred minister become, together with Christ, "a pure victim, a holy victim, an immaculate victim". In order carefully to preserve unstained this inestimable treasure of our chastity, it is suitable and necessary to be obedient to that exhortation of the Prince of Apostles, which we daily repeat in the Divine Office, "Be ye sober, and watch". (Papal Writings, Menti Nostrae, 23 September 1960).