11 The Shepherd and Bishop of our souls so constituted his Church that the people whom he chose and acquired by his blood would have its priests to the end of time, and that Christians would never be like sheep without a shepherd. Recognizing Christ's desire, and at the inspiration of the Holy Spirit, the apostles considered it their duty to select men "who will be capable of teaching others" (2 Tim 2:2). This duty, then, is a part oœ the priestly mission by which every priest becomes a sharer in the care of the whole Church, lest ministers be ever lacking for the People of God on earth. Since, however, there is common cause between the captain of a ship and the sailors, let all Christian people be taught that it is their duty to cooperate in one way or another, by constant prayer and other means at their disposal, that the Church will always have a sufficient number of priests to carry out her divine mission. In the first place, therefore, it is the duty of priests, by the ministry of the word and by the example of their own lives, showing forth the spirit of service and the paschal joy to demonstrate to the faithful the excellence and necessity of the priesthood; then they should see to it that young men and adults whom they judge worthy of such ministry should be called by their bishops to ordination, sparing no effort or inconvenience in helping them to prepare for this call, always saving their internal and external freedom of action. In this effort, diligent and prudent spiritual direction is of the greatest value. Parents and teachers and all who are engaged in any way in the education of boys and young men should so prepare them that they will recognize the solicitude of our Lord for his flock, will consider the needs of the Church, and will be prepared to respond generously to our Lord when he calls, saying: "Here I am Lord, send me" (Is 6:8). This voice of the Lord calling, however, is never to be expected as something which in an extraordinary manner will be heard by the ears of the future priest. It is rather to be known and understood in the manner in which the will of God is daily made known to prudent Christians. These indications should be carefully noted by priests. Works favoring vocations, therefore, whether diocesan or national, are highly recommended to the consideration of priests. In sermons, in catechetical instructions, and written articles, priests should set forth the needs of the Church both locally and universally, putting into vivid light the nature and excellence of the priestly ministry, which consoles heavy burdens with great joys, and in which in a special way, as the Fathers of the Church point out, the greatest love of Christ can be shown.
Source: Presbyterorum Ordinis (Vatican.va)