89 Before concluding, we turn Our thoughts and Our words, with very special tenderness to you who are still in your studies for the priesthood; and urge you from the depth of Our heart to prepare yourselves with all seriousness for the great task to which God calls you. You are the hope of the Church and of the people, who look for so much, or rather everything, to you. For to you they look for that living and life-giving knowledge of God and of Jesus Christ, in which is eternal life. In piety, purity, humility, obedience, discipline and study strive then to make yourselves priests after the Heart of God. We assure you that in the task of fitting yourselves for the priesthood by solid virtue and learning, no care, no diligence, no energy can be too great; because upon it so largely depend all your future apostolic labors. See to it that on the day of your ordination to the priesthood, the Church find you in fact such as she wishes you to be, that is "replenished with heavenly wisdom, irreproachable in life and established in the ways of grace," so that "the sweet odor of your life may be a delight to the Church of Christ, that both by word and good example you may build the house, that is, the family of God."
Source: Ad Catholici Sacerdotii (Vatican.va)