19 (Study and pastoral knowledge.) Priests are admonished by their bishop in the sacred rite of ordination that they "be mature in knowledge" and that their doctrine be "spiritual medicine for the People of God." The knowledge of the sacred minister ought to be sacred because it is drawn from the sacred source and directed to a sacred goal. Especially is it drawn from reading and meditating on the Sacred Scriptures, and it is equally nourished by the study of the Holy Fathers and other Doctors and monuments or tradition. In order, moreover, that they may give apt answers to questions posed by men of this age, it is necessary for priests to know well the doctrines of the magisterium and the councils and documents of the Roman pontiffs and to consult the best of prudent writers of theological science. Since human culture and also sacred science has progressed in our times, priests are urged to suitably and without interruption perfect their knowledge of divine things and human affairs and so prepare themselves to enter more opportunely into conversation with their contemporaries. Therefore, let priests more readily study and effectively learn the methods of evangelization and the apostolate. Let opportune aids be prepared with all care, such as the institution of courses and meetings according to territorial conditions, the erection of centers of pastoral studies, the establishment of libraries, and the qualified supervision of studies by suitable persons. Moreover, let bishops, either individually or united in groups, see to it that all their priests at established intervals, especially a few years after their ordination, may be able to frequent courses in which they will be given the opportunity to acquire a fuller knowledge of pastoral methods and theological science, both in order that they may strengthen their spiritual life and mutually communicate their apostolic experiences with their brothers. New pastors and those who have newly begun pastoral work, as well as those who are sent to other dioceses or nations, should be helped by these and other suitable means with special care. Finally, the bishops will be solicitous that there will be some who dedicate themselves to a deeper study of theology, that there will not be lacking suitable teachers for the formation of clerics, that the rest of the priests and the faithful will be helped to acquire the doctrine they need, and that healthy progress will be encouraged in the sacred disciplines, so necessary for the Church.
Source: Presbyterorum Ordinis (Vatican.va)