S Pius V: "whoever enters through the gate is the shepherd of the sheep"

Whoever enters through me will be saved,
and will come in and go out and find pasture.

--Jn 10:1-10

The Lord made Simon alone, whom he named Peter, the "rock" of his Church. He gave him the keys of his Church and instituted him shepherd of the whole flock. "The office of binding and loosing which was given to Peter was also assigned to the college of apostles united to its head." This pastoral office of Peter and the other apostles belongs to the Church's very foundation and is continued by the bishops under the primacy of the Pope.

-- CCC 881