A common stumbling block for non-Catholics is the role of the Pope, as the Vicar of Christ and the leader of the Church on Earth. Many misunderstand the actual role of the Pope, and misinterpret the authority that he has been given.
In the Gospel of Matthew, chapter 16:18, Jesus says to Peter “and so I say to you, you are Peter, and upon this rock I will build my Church, and the gates of the netherworld shall not prevail against it.” Among Jesus’ twelve apostles, Peter is given a unique mission to preserve the purity and sanctity of the Holy Church, and lead his fellow brothers and sisters in the one true faith. In like manner, Jesus endowed the other apostles with the authority of bishops, with Peter as their head. In this way, they formed a “college”, or stable group dedicated to teaching, and defending the faith. Just as Peter and his fellow apostles together formed an apostolic college, so too does the pope, successor of Peter, and bishop of Rome, along with the other bishops, form an episcopal college, dedicated to instructing and preserving the faith. Since the Church was intended to endure through the ages, until the return of Jesus, succession was necessary in order for this to be fulfilled. In fact, there has been an unbroken succession of popes from Peter to Benedict XV1, the 265th successor.
Peter, along with succeeding Popes and bishops were and are given the authority to govern the Church, make doctrinal judgments, and implement definitive teachings regarding faith and morals. However, the Teaching office of the Church may be exercised by the Pope alonewhen he teaches officially, or by the whole "college" of bishops together with the Pope. It must be stated however, that the Pope is not infallible on all matters. The word "infallible" does not mean that the Pope is perfect. It also does not mean that the Pope knows everything. Instead, "infallibility" only applies when the Pope speaks about solemn, official teachings on faith and morals. This does not happen very often and usually is in response to a doctrine that has been called into question. This teaching is based on the promise Christ gave to His Church in John 16:13 that the Holy Spirit would "guide you to all truth." However, on the occasion that the Church declares a particular matter as infallible, this means it is something believed to be revealed by Jesus Christ and is without the possibility of error. When a particular matter is declared infallible, Catholics are obliged to adhere in the spirit of obedience. In the Dogmatic Constitution on the Church, Lumen Gentium, the nature of infallibility is explained:
“Bishops who teach in communion with the Roman Pontiff are to be revered by all as witnesses of divine and Catholic truth; the faithful, for their part, are obliged to submit to their bishops' decision, made in the name of Christ, in matters of faith and morals, and to adhere to it with a ready and respectful allegiance of mind.” (Lumen Gentium, 25)
The primacy of the Pope, and the recognition of the universal authority he has been given to instruct the faithful, sustains and safeguards the unity of the Church as the communicator of truth. It has been said that the Pope is the servant of the servants of God. That is to say, the Pope's primary mission is one of service to the people of God, to uphold the oneness of Christ’s Church.