One of the hallmarks of the Roman Catholic Church (RCC) is their claim to be Apostolic. The RCC teaches that Christ gave authority over the Church to the Apostles who became the first bishops of the Church. That authority is also given to all future bishops as successors of the Apostles.
"The Church is apostolic. She is built on a lasting foundation: "the twelve apostles of the Lamb" (Rev 21:14). She is indestructible (cf. Mt 16:18). She is upheld infallibly in the truth: Christ governs her through Peter and the other apostles, who are present in their successors, the Pope and the college of bishops." CCC 869
The Bishop of Rome (the Pope) is the successor of Peter and the chief ruler of the RCC.
"The Pope, Bishop of Rome and Peter's successor, "is the perpetual and visible source and foundation of the unity both of the bishops and of the whole company of the faithful." "For the Roman Pontiff, by reason of his office as Vicar of Christ, and as pastor of the entire Church has full, supreme, and universal power over the whole Church, a power which he can always exercise unhindered."" CCC 882
The Pope and the Bishops form the teaching authority of the RCC, called the “magisterium”. When teaching on doctrines pertaining to faith and morals, they are considered “infallible” or free from error.
"The magisterium, guided and protected from error by the Holy Spirit, gives us certainty in matters of doctrine. The Church is the custodian of the Bible and faithfully and accurately proclaims its message, a task which God has empowered it to do…Such an official interpreter is absolutely necessary if we are to understand the Bible properly…The magisterium is infallible when it teaches officially…" excerpt from Catholic.com
""The Roman Pontiff, head of the college of bishops, enjoys this infallibility in virtue of his office, when, as supreme pastor and teacher of all the faithful - who confirms his brethren in the faith he proclaims by a definitive act a doctrine pertaining to faith or morals. . . . The infallibility promised to the Church is also present in the body of bishops when, together with Peter's successor, they exercise the supreme Magisterium," above all in an Ecumenical Council. When the Church through its supreme Magisterium proposes a doctrine "for belief as being divinely revealed," and as the teaching of Christ, the definitions "must be adhered to with the obedience of faith." This infallibility extends as far as the deposit of divine Revelation itself." CCC 891
The RCC maintains that God speaks to the Church through both the Sacred Scripture (the Bible) and Sacred Tradition (traditions handed down from the Apostles). However, for proper interpretation, it is necessary for all truths to come from the magisterium. Personal interpretation of the Bible is not allowed.
"As from the first, God speaks to his Church through the Bible and through sacred Tradition. To make sure we understand him, he guides the Church’s teaching authority—the magisterium—so it always interprets the Bible and Tradition accurately. This is the gift of infallibility. Like the three legs on a stool, the Bible, Tradition, and the magisterium are all necessary for the stability of the Church and to guarantee sound doctrine." excerpt from Catholic.com
"As a result the Church, to whom the transmission and interpretation of Revelation is entrusted, "does not derive her certainty about all revealed truths from the holy Scriptures alone. Both Scripture and Tradition must be accepted and honored with equal sentiments of devotion and reverence."" CCC 82
"Mindful of Christ's words to his apostles: "He who hears you, hears me", the faithful receive with docility the teachings and directives that their pastors give them in different forms." CCC 87
"Some Christians claim, "The Bible is all I need," but this notion is not taught in the Bible itself. In fact, the Bible teaches the contrary idea (2 Pet. 1:20–21, 3:15–16). The "Bible alone" theory was not believed by anyone in the early Church. It is new, having arisen only in the 1500s during the Protestant Reformation. The theory is a "tradition of men" that nullifies the Word of God, distorts the true role of the Bible, and undermines the authority of the Church Jesus established (Mark 7:1–8). Although popular with many "Bible Christian" churches, the "Bible alone" theory simply does not work in practice. Historical experience disproves it. Each year we see additional splintering among "Bible-believing" religions. Today there are tens of thousands of competing denominations, each insisting its interpretation of the Bible is the correct one. The resulting divisions have caused untold confusion among millions of sincere but misled Christians." excerpt from Catholic.com
To summarize, the RCC relies on two forms of revelation from God – Scripture and Tradition. However, only the magisterium has the authority to interpret these revelations and all of the members of the Church must accept the teachings of their leadership with submission. This authority of the magisterium (and infallibility in teaching doctrine) is based on the idea of apostolic succession which is supported by the magisterium’s interpretation of the Scriptures.
I think in the next post we will look at the Sacraments as they are a big part of the RCC and important to the RCC's message of salvation.