54 To these students We would like not only to reveal the affection We feel for them, but also to exhort them, urgently and lovingly, to carry their heads high and proud, marked with the sign of Jesus' blood and with the sacred chrism; We would like to exhort them during their stay abroad never to bypass an opportunity not only to acquire the right professional training but also to achieve perfection in their religious education. Although they will be exposed to dangers and evils, they will nevertheless have a wonderful opportunity to share in many spiritual advantages while living in Catholic countries, if all the faithful remember that, whoever and wherever they are, they must be a good example to others and bring mutual edification to one another.
Source: Princeps Pastorum (Vatican.va)