§1. The instruction of students is to provide that they have solicitude not only for the particular church in whose service they are to be incardinated but also for the universal Church, and that they show themselves prepared to devote themselves to particular churches which are in grave need.
§2. The diocesan bishop is to take care that clerics intending to move from their own particular church to a particular church of another region are suitably prepared to exercise the sacred ministry there, that is, that they learn the language of the region and understand its institutions, social conditions, usages, and customs.
Source: Code of Canon Law (Vatican.va)