38 All bishops, as members of the body of bishops succeeding to the College of Apostles, are consecrated not just for some one diocese, but or the salvation of the entire world. The mandate of Christ to preach the Gospel to every creature (Mark 16:15) primarily and immediately concerns them, with Peter and under Peter. Whence there arises that communion and cooperation of churches which is so necessary today for carrying on the work of evangelization. In virtue of this communion, the individual churches bear the burden of care for them all, and make their necessities known to one another, and exchange mutual communications regarding their affairs, since the extension of the Body of Christ is the duty of the whole College of Bishops. In his own diocese, with which he constitutes one unit the bishop, stimulating, promoting and directing the work for the missions, makes the mission spirit and zeal of the People of God present and as it were visible, so that the whole diocese becomes missionary. It will be the bishop's task to raise up from among his own people, especially the sick and those oppressed by hardship, some souls to offer prayers and penance to God with a wide - open heart for the evangelization of the world. The bishop will also gladly encourage youths and clerics who have vocations to mission institutes, accepting it with a grateful spirit if God should call some of them to be employed in the missionary activity of the Church. The bishop will exhort and help the diocesan congregations to play a role of their own in the missions; he will promote the works of mission institutes among his own faithful, but most especially the papal mission works. For it is only right to give these works pride of place, since they are the means of imbuing Catholics from their very infancy with a real universal and missionary outlook; and they are also the means of making an effective collection of funds to subsidize all missions, each according to its needs. But since the need for workers in the vineyard of the Lord is growing from day to day, and diocesan priests have expressed the wish to play an ever greater part in the evangelization of the world, this sacred synod desires that the bishops considering the very serious dearth of priests which is hindering the evangelization of many areas, should send some of their better priests, who offer themselves for mission work and have received a suitable preparation, to those dioceses which are lacking in clergy, where at least for a time they will exercise their missionary ministry in a spirit of service. But in order that the missionary activity of the bishops may be exercised more effectively for the good of the whole Church, it would be expedient for the episcopal conferences to take charge of those affairs which concern the orderly cooperation of their own region. In their own conference, the bishops should deliberate about dedicating to the evangelization of the nations some priests from among the diocesan clergy; they should decide what definite offering each diocese should be obliged to set aside annually for the work of the missions, in proportion to its own budget; they should consider how to direct and control the ways and means by which the missions receive direct help; they should deal with assisting and if need be, founding, missionary institutes and seminaries for diocesan mission clergy, and the promoting of closer relations between such institutes and the dioceses. It also pertains to the episcopal conferences to found and promote works for the brotherly reception and due pastoral care of those who immigrate from mission lands for the sake of studying or finding work. For through them, far - away peoples are sometimes made near; and an excellent opportunity is offered to communities which have long been Christian to converse with nations which have not yet heard the Gospel, and to show them in their own dutiful love and aid, the genuine face of Christ.
Source: Ad Gentes (Vatican.va)