Why do Catholics Believe in the Papacy? *
In the Book of Isaiah, God promises that he will appoint a new master of the royal household of his people: "He shall be a father to the inhabitants of Jerusalem, and to the house of Judah. I will place the key of the House of David on his shoulder; when he opens, no one shall shut, when he shuts, no one shall open" (22:21-22)
The Book of Revelation refers this prophecy to Jesus as the new master of God's household--the "new Jerusalem" (21:2), which is the Church. St. John calls him "the holy one, the true, who holds the key of David, who opens and no one shall close, who closes and no one shall open" (3:7).
These passages take on additional significance when we read in the Gospel according to Matthew that Jesus gives a special commission to his chief apostle: "You are Peter (meaning literally, "Rock"), and upon this rock I will build my church" (16:18). This is the most direct biblical reference to the papacy. In this moment, our Lord establishes St. Peter as the first pope and leader of the Church, whose role is indispensable to its mission.
Now notice what Jesus goes on to say to Peter at his commission: "I will give you the keys to the kingdom of heaven. Whatever you bind on earth shall be bound in heaven; and whatever you loose on earth shall be loosed in heaven" (16:19).
Here Jesus tells more about what it means for Peter to be the "Rock" of the Church: Peter and his successors will have a unique share in Christ's authority as the keeper of the "keys." Alluding to the prophecy in Isaiah, Jesus foretells the role of the pope as a father to God's people (the word "pope" literally means "father), the head of God's royal household, the one with divine authority to open and close the way to the heavenly kingdom.
If such an office was needed in the first generation of the Church, then it is also necessary in every generation, as in the case of priests and bishops. St. Peter became the first bishop of Rome, so his unique office in the Church has been passed down to his episcopal successors there.
Other related scriptures: Mt 17: 24-27; Mk 16:17; Lk 22:32; Jn 21:15-17; Acts 2:14-36; 3:1-16; 5:1-11; 15:7-11; 1 Pt 5:1.
Catechism of the Catholic Church: 440-443; 552-556; 737; 765; 768; 771; 815-816; 834; 862; 874-887; 891; 914; 936-937; 981; 1444; 2034-2035.
*Quoted from The New Catholic Answer Bible. Wichita, Kansas, Fireside Catholic Publishing, 2005. www.firesidecatholic.com
Additional insights at: www.catholic.com