Catechism of the Catholic Church §942 — excerpt
By virtue of their prophetic mission, lay people "are called . . to be witnesses to Christ in all circumstances and at the very heart of the community of mankind" (GS 43 # 4).
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.