65 Now if the people are trained in this truly Catholic attitude in the domestic circle, in the schools, in the parishes, in Catholic Action groups, and in other pious societies, there can be no doubt that they will give the Church those ministers she needs in preaching the divine message to all nations. Nor should this point be overlooked: if an enthusiastic interest in the missions is aroused in your particular dioceses, it will be a pledge of the renewal of religion and devotion in the minds and hearts of your people. It is impossible for a Christian community to perish that gives its sons and daughters to the Church. Consequently, if the supernatural life is the fruit of charity and is increased by the spirit of self dedication, one may rightly assert that the Catholic life of any nation is measured by its generosity in supporting and maintaining the missionary activity of the Church.
Source: Fidei Donum (Vatican.va)