Why does the Catholic Church believe that it has a teaching authority?
The Catholic Church teaches that the Holy Spirit guides the Church to all truth. This is based on Christ's promise that "when he comes, the Spirit of truth, he will guide you to all truth. He will not speak on his own, but he will speak what he hears, and will declare to you the things that are coming." (John 16:13) Jesus told this to his apostles on the night before he died. After his resurrection, Jesus breathed on his apostles and told them, "receive the Holy Spirit. Whose sins you forgive are forgiven them, and whose sins you retain are retained." (John 20:22 – 23)
Having been promised the Holy Spirit to guide them to all truth, the Apostles then went forth and proclaimed the Gospel of Jesus without error. When others in the church taught an understanding of the faith which was contrary to what the Apostles understood, the Apostles would correct the mistake knowing that they were guided by the Holy Spirit. For example, St. Paul wrote to the Galatians, "but even if we or an angel from heaven should preach a gospel other than the one that we preached to you, let that one be accursed!" (Gal 1:8) In the rest of the letter goes on to correct the mistaken teaching, exercising the authority given to him by Christ's promise that he would be guided to all truth.
The question is, how does God accomplish this guidance? Does God guide each Christian individually to all truth? What happens, then, when Christians disagree about the fundamentals?
Won’t following the Magisterium inhibit my freedom?
The Church never forces you to do or believe anything. Instead, the teaching role of the Church is to proclaim the truth, and, because the Church is guided by the Holy Spirit, we can be confident that those proclamations are true. Imagine you are playing Who Wants to Be a Millionaire, and one of the lifelines is the "Right Answer" lifeline for questions on faith and morals. Wouldn't you want that lifeline? Or, to look at in a more relevant context, if you were one of the people in Galatia almost 2000 years ago who had come to believe something other than the fullness of what Christ had revealed, wouldn’t you want St. Paul to correct you in his letter? Clearly, St. Paul did not expect that each Christian would be guided by the Holy Spirit individually to the fullness of truth, otherwise he would not have written a letter correcting their understanding. The challenge is to discern whether the Church really has this authority without being influenced by the difficulty of the message. It is one thing to reject the teaching authority because you truly do not believe that it is from God, but it is different to reject it because you don’t like the message being taught.
It’s worth noting that the message is difficult. Jesus told us that it would be difficult. He said, "Whoever wishes to come after me must deny himself, take up his cross, and follow me." (Mark 8:34) Crosses are not easy things. St. Paul also taught that following Jesus was difficult. He acknowledged that there is a war that goes on inside us between the part of us that desires to follow Christ and the part of us that is attached to sin. This is a great challenge.
All of us follow a magisterium – a definitive teacher, the person who decides what is true and what is not true. For many of us, we fulfill that role ourselves. Sometimes, though, we give that authority to a Scripture scholar or minister, or perhaps a friend or relative whom we admire.
Why does the Church think that the role of the Magisterium belongs to the Pope and the bishops?
As already mentioned, Jesus gave His own authority to the Apostles (see Matthew 16:19 and 18:18). We recognize in the Acts of the Apostles and in the epistles that the Apostles exercised this authority fully. They spoke out against people who attempted to modify the one Faith of the Church and to lead others away from what the Apostles had originally taught. Paul wrote, “If any one is preaching to you a gospel contrary to that which you received, let him be accursed.” (Gal 1:9b) They kicked other Christians out of the Church in order to help those Christians come to conversion (see, for example, 1 Corinthians 5:1-5, 9-13). They identified other leaders to preach the Gospel and lead the established communities, and they gave those leaders the authority to choose other leaders (called bishops) for the Church (see, for example, Titus 1:5 and following).
Around 80 AD (which is possibly before the Gospel of John was written, often estimated around 90 AD), St. Clement of Rome wrote a Letter to the Corinthians. In it he describes the succession of the bishops. He wrote:
The Apostles received the gospel for us from the Lord Jesus Christ, and Jesus Christ was sent from God. Christ, therefore, is from God, and the Apostles are from Christ. Both of these orderly arrangements then are by God’s will. Receiving their instructions and being full of confidence on account of the resurrection of our Lord Jesus Christ, and confirmed in faith by the word of God, they went forth in the complete assurance of the Holy Spirit, preaching the good news that the Kingdom of God is coming. Through countryside and city they preached, and they appointed their earliest converts, testing them by the spirit, to be the bishops and deacons of future believers. (Letter to Corinthians, 42, 1)
In the Acts of the Apostles, St. Peter recognizes that the position of “Apostle” is an office (see Acts 1:20), in which the bearer of the office can be replaced. So, they replace Judas Iscariot with Matthias. As Clement notes, this understanding of the office is continued after the Apostles died, with the authority of their office handed on to the bishops who replaced them. According to the early practice of the Church, this succession was accomplished and celebrated using a ritual that included a laying-on of the hands by those who were already Apostles or bishops.
The Catechism of the Catholic Church teaches, “Christ himself chose the apostles and gave them a share in his mission and authority. Raised to the Father’s right hand, he has not forsaken his flock but he keeps it under his constant protection through the apostles, and guides it still through these same pastors who continue his work today. Thus, it is Christ whose gift it is that some be apostles, others pastors. He continues to act through the bishops.” (CCC 1575)