The chief responsibilities of the Pope and the bishops are to teach, sanctify, and govern the People of God. This authority and power was given to them by Jesus, beginning with that received by St. Peter and the other Apostles.
After His Resurrection, Jesus demanded of Peter a profession of love. “He said to him the third time, ‘Simon, son of John, do you love me?’…And he said to him, ‘Lord you know everything; you know that I love you.’ Jesus said to him, ‘Feed my sheep’” (John 21:17).
Jesus willed that the bishops, the successors of the Apostles, should be shepherds in His Church. He placed Peter over the other Apostles and instituted him as a permanent source and foundation of unity, faith, and fellowship.
“And I tell you, you are Peter, and on this rock I will build my church, and the powers of death shall not prevail against it. I will give you the keys of the kingdom of heaven, and whatever you bind on earth shall be bound in heaven, and whatever you loose on earth shall be loosed in heaven” (Matthew 16:18-19).
The Roman Pontiff, the head of the College of Bishops, is guaranteed doctrinal infallibility in virtue of his office, when, as the supreme shepherd and teacher of all the faithful, he proclaims by a definitive act some doctrine of faith and morals.
Infallibility is a gift of the Holy Spirit which protects the Church’s faith from error. The Holy Spirit remains in the Catholic Church to enable it to continue the saving work of Jesus in the world. He guides the bishops, priests, and deacons in their holy work of teaching Christ’s doctrine, shepherding souls, and giving grace to the people through the sacraments.
When the Catholic Church teaches solemnly in the name of God in matters of faith and morals, the teaching is infallible; that is, it cannot be mistaken. When the Pope teaches solemnly as head of the Church, or when bishops assembled with the Pope in council solemnly pronounce upon a matter of faith or morals, that doctrine is the infallible teaching of the Church. It must receive the assent of faith.
Moreover, when the Pope and the bishops throughout the world who are in union with him teach that a certain doctrine has been revealed by God, this teaching is infallible, even though it has not been solemnly defined, for it is still Christ teaching through His universal Church. When the Pope speaks to the whole Church on a matter of faith or morals, but not ex cathedra, his teaching, nevertheless, demands respect, obedience, and assent.