Catechism of the Catholic Church §92 — excerpt
"The whole body of the faithful. . cannot err in matters of belief. This characteristic is shown in the supernatural appreciation of faith (sensus fidei) on the part of the whole people, when, from the bishops to the last of the faithful, they manifest a universal consent in matters of faith and morals."
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: LG 12 · St. Augustine, De praed. sanct. 14, 27: PL 44, 980