45 In dealing with the family the Supreme Pontiff affirmed that the private ownership of material goods has a great part to play in promoting the welfare of family life. It "secures for the father of a family the healthy liberty he needs in order to fulfil the duties assigned him by the Creator regarding the physical, spiritual and religious welfare of the family." (22) It is in this that the right of families to migrate is rooted. And so Our Predecessor, in speaking of migration, admonished both parties involved, namely the country of departure and the country receiving the newcomers, to seek always "to eliminate as far as possible all obstacles to the birth and growth of real confidence" (24) between the nations. In this way both will contribute to, and share in, the increased welfare of man and the progress of culture.
Source: Mater et Magistra (Vatican.va)