Catechism of the Catholic Church

"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 by Christ himself, the Good Shepherd and Prince of Shepherds, who gave his life for his sheep. (857)