56 We exhort all the bishops, the clergy, and the faithful of the dioceses of the whole world, who are contributing to relieve the spiritual and material necessities of the missions by their prayers and offerings, to increase voluntarily their badly needed contributions. Despite the scarcity of priests which besets even the pastors of the oldest dioceses, there should be no hesitation in encouraging missionary vocations and in releasing the very best and most useful laymen, that they may be placed at the disposal of the new dioceses; heavenly consolations will soon be derived from this sacrifice, made for the furtherance of God's cause.
Source: Princeps Pastorum (Vatican.va)