25 It is clear, however, that the Church cannot be properly and duly established in new territories, unless all is there organized as time and circumstances require and especially unless a native clergy equal to the need has been properly educated and trained. In this connection We should like to borrow the grave and wise directives of the Encyclical Letter Rerum Ecclesiae : ". . . While each of you should try to have as large a number of native students as possible, you must further make it your aim to fashion and develop in them sacerdotal sanctity and such an apostolic spirit and zeal for the salvation of their own people that they will be ready to lay down their lives for their fellow-tribesmen and fellow-countrymen.
Source: Evangelii Praecones (Vatican.va)