39 Priests personally represent Christ, and are collaborators of the order of bishops in that threefold sacred task which by its very nature belongs to the mission of the Church. Therefore, they should fully understand that their life is also consecrated to the service of the missions. Now because by means of their own ministry - which consists principally in the Eucharist which perfects the Church - they are in communion with Christ the Head and are leading others to this communion, they cannot help but feel how much is yet wanting to the fullness of that Body, and how much therefore must be done that it may grow from day to day. They shall therefore plan their pastoral care in such a way that it will serve to spread the Gospel among non - Christians. In their pastoral activities, priests should stir up and preserve amid the faithful a zeal for the evangelization of the world, by instructing them in sermons and in Christian doctrine courses about the Church's task of announcing Christ to all nations; by enlightening Christian families about the necessity and the honor of fostering missionary vocations among their own sons and daughters, by promoting mission fervor in young people from the schools and Catholic associations so that among them there may arise future heralds of the Gospel. Let priests teach the faithful to pray for the missions, and let them not be ashamed to ask alms of them for this purpose, becoming like beggars for Christ and for the salvation of souls. Professors in seminaries and universities will teach young people the true state of the world and of the Church, so that the necessity of a more intense evangelization of non - Christians will become clear to them and will nurture their zeal. In teaching the dogmatic, biblical, moral, and historical branches, they should focus attention on the missionary elements therein contained, so that in this way a missionary, awareness may be formed in future priests.
Source: Ad Gentes (Vatican.va)