72 These young men, uprooted by the social upheavals in their own countries, for many reasons often do not enjoy sufficient Catholic social contacts among the people who are giving them hospitality. Owing to this their Christian lives may be endangered, as the true values and excellences of the new culture they are seeking may escape them and they may be, in consequence, seduced by the doctrines of materialism and may succumb to the blandishments of atheistic coteries. You cannot ignore the impact of this on their present and future careers. It would be a good idea to appoint some devout and well-equipped members of the clergy to take charge of this apostolate, thus relieving the anxieties of their own bishops in the mission fields.
Source: Fidei Donum (Vatican.va)