Catechism of the Catholic Church §1948 — excerpt
Solidarity is an eminently Christian virtue. It practices the sharing of spiritual goods even more than material ones.
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.