Catechism of the Catholic Church §899 — excerpt
The initiative of lay Christians is necessary especially when the matter involves discovering or inventing the means for permeating social, political, and economic realities with the demands of Christian doctrine and life.
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.
Also cites: Pius XII, Discourse, February 20, 1946: AAS 38 (1946) 149 · quoted by John Paul II, CL 9