The Roman Pontiff, as the successor of Peter, is the perpetual and visible principle and foundation of unity of both the bishops and of the faithful.
LUMEN GENTIUM, 23
The Pope is the successor of St. Peter, who Jesus called the “rock” on which the Church was to be built and to whom the “keys” of the kingdom of heaven were entrusted. As Vicar of Jesus Christ, the Pope governs the Catholic Church as its supreme head. The Pope, as Bishop of Rome, is the chief pastor and shepherd of the whole Church.
The Scriptures make it clear that Christ chose Peter as head of His Church. Peter was commissioned by Christ to continue his mission and ministry. Peter’s leadership in the early church, after the Ascension of the Lord, is clearly established in the Acts of the Apostles. More than simply establishing a single person as supreme head of the church, Christ instituted a perpetual office of leadership, which is the institution of the papacy. We as Catholics believe that the present Pope follows in apostolic succession in line with the supremacy entrusted to St. Peter. The permanence of the office of chief pastor, first held by Peter, is essential to the very being of the Church.
The Pope has therefore been established by Christ to be the supreme teacher and ruler of the Church. In fulfilling this office, the Pope is called to protect what is to be believed by all the faithful and to preserve the tradition of faith handed on through the generations.
The Pope is responsible for many things. He teaches on matters of morals and faith, has responsibility for the liturgical life of worship of the Church, is responsible for the canonization of saints, has supreme judicial authority and makes all appointments to the public offices of the church.
2009, Archdiocese of Boston