Catechism of the Catholic Church §754 — excerpt
"The Church is, accordingly, a sheepfold, the sole and necessary gateway to which is Christ. It is also the flock of which God himself foretold that he would be the shepherd, and whose sheep, even though governed by human shepherds, are unfailingly nourished and led…
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 6