27 But, Venerable Brethren, this weapon will lose much of its efficacy or be altogether useless in the hands of men not accustomed to the interior life with Christ, not educated in the school of true and solid piety, not thoroughly inflamed with zeal for the glory of God and for the propagation of His kingdom. So keenly did Gregory feel this necessity that he used the greatest care in creating bishops and priests animated by a great desire for the divine glory and for the true welfare of souls. And this was the intent he had before him in his book on the Pastoral Rule , wherein are gathered together the laws regulating the formation of the clergy and the government of bishops - laws most suitable not for his times only but for our own. Like an "Argus full of light," says his biographer, "he moved all round the eyes of his pastoral solicitude through all the extent of the world" (Joann. Diac., lib ii. c. 55), to discover and correct the failings and the negligence of the clergy. Nay, he trembled at the very thought that barbarism and immortality might obtain a footing in the life of the clergy, and he was deeply moved and gave himself no peace whenever he learned of some infraction of the disciplinary laws of the Church, and immediately administered admonition and correction, threatening canonical penalties on transgressors, sometimes immediately applying these penalties himself, and again removing the unworthy from their offices without delay and without human respect.
Source: Iucunda Sane (Vatican.va)