"When there are just reasons in favor of it, he must be permitted to emigrate to other countries and take up residence there. The fact that he is a citizen of a particular State does not deprive him of membership in the human family, nor of citizenship in that universal society, the common, world-wide fellowship of men." (Pacem in Terris, no. 25)
"And among man's personal rights we must include his right to enter a country in which he hopes to be able to provide more fittingly for himself and his dependents. It is therefore the duty of State officials to accept such immigrants and—so far as the good of their own community, rightly understood, permits—to further the aims of those who may wish to become members of a new society." (Pacem in Terris, no. 106)
"The Church acts in continuity with Christ's mission. In particular, she asks herself how to meet the needs, while respecting the law of those persons who are not allowed to remain in a national territory. She also asks what the right to emigrate is worth without the corresponding right to immigrate." (Pope John Paul II, Undocumented Migrants, Message for World Migration Day, 1996, no. 3)
"...expression and movement, the possibility to satisfy basic needs such as food, health care, work, housing and education; the frustration of these needs forces many into a position where their only option is to emigrate." (Migration With a View to Peace, no. 3)