13. "In the education of clerics two elements are essential: learning for the development of the mind and virtue for the perfection of the soul. To the humanistic curriculum by which youths are educated must be added sacred and canonical studies. Care must be taken that their content is sound, entirely pure, and in full harmony with the documents of the Church; today especially the style must be forceful and eloquent, so that he may be able to exhort . . . and to refute those who contradict. - Holiness of life without which knowledge puffs up and does not edify, consists not only in good and honorable habits, but also in that body of sacerdotal virtues which makes good priests exemplars of Jesus Christ the eternal High Priest. . . . In these institutions take care that the men appointed as teachers be men of sound doctrine and good morals, men to whom you can entrust a matter of such great importance. Choose rectors and spiritual directors who are outstanding for prudence, counsel, and experience. The common life and discipline should be so arranged by your authority that the students will never offend against piety; furthermore there should be an abundance of all aids which nourish piety, so that the seminarians may make daily progress in acquiring the virtues proper to the sacerdotal state."