9 We desire likewise that they should insist on the faithful observance of the rules contained in a still more recent document, which in a particular manner regards the lectures on anything else that could give occasion to the young men to take part in external agitations.(10) Thus the students of the seminaries, treasuring up this time, so precious and full of the greatest tranquillity for their souls, will be able to devote themselves entirely to those studies which will render them fitted for the grand duties of the priesthood, particularly that of the ministry of preaching and the confessional. They should reflect well on the gravity of the responsibilities of those priests who in spite of the great need of the Christian people neglect to devote themselves to the exercise of the sacred ministry, and of those also who, not bringing to it an enlightened zeal for both the one and the other, correspond sadly with their vocation in things which are of the greatest importance in the salvation of souls.
Source: Fin dal Principio (Vatican.va)