Catechism of the Catholic Church §1142 — excerpt
But "the members do not all have the same function." Certain members are called by God, in and through the Church, to a special service of the community.
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: PO 2 · 15