7 Finally, there must be respect for antiquity; whatever we see advantageously established in times past must be religiously preserved. Now, it was the practice of the Apostles first to instruct the multitude in Christian precepts, then to select several from the people and initiate them into the sacred mysteries and even elevate them to the episcopacy. This example was followed afterwards by the Roman pontiffs. Their custom has always been to direct missionaries to exert every means to select a native clergy wherever the Christian community grew sufficiently large. To take care, therefore, of the preservation and propagation of the Catholic religion among the Hindus, a Hindu clergy has to be formed that could administer the sacraments and govern the Christian people properly, no matter how menacing the times.
Source: Ad Extremas (Vatican.va)