In the Old Testament, keys have always been used as a symbol of power and authority for the Jews. He who has the key has all authority over who enters through the locked door. If He shuts, no one can open. If He opens, no one can shut.
In Revelation 3:7-8, it reads: “To the angel of the church in Philadelphia write: These are the words of him who is holy and true, who holds the key of David. What he opens no one can shut, and what he shuts no one can open. I know your deeds. See, I have placed before you an open door that no one can shut. I know that you have little strength, yet you have kept my word and have not denied my name.”
Then, what is this key of David? What is its significance? In Isaiah 22:20-24, it has been prefigured: “In that day I will summon my servant, Eliakim son of Hilkiah. I will clothe him with your robe and fasten your sash around him and hand your authority over to him. He will be a father to those who live in Jerusalem and to the people of Judah. I will place on his shoulder the key to the house of David; what he opens no one can shut, and what he shuts no one can open. I will drive him like a peg into a firm place; he will become a seat of honor for the house of his father. All the glory of his family will hang on him: its offspring and offshoots—all its lesser vessels, from the bowls to all the jars.” Here, the Jewish name Eliakim means “God will establish” — someone whom God will exalt. In several verses in Scripture, whenever Eliakim is mentioned, he is also shown to be “Over the Household” (see 2 Kings 18:18, 37, 19:2; Isaiah 36:3, 22, 37:2). When Eliakim was appointed to succeed Shebna as governor of the palace in the reign of King Hezekiah of Judah, he would be a FATHER in robe and sash who held the authority through the key of David ruling from a firm place.
However, when Christ came, this authority was handed over to a man whom He exalted as the chief of the apostles. And who is this man? In Matthew 16:17-19, Jesus said: “Blessed are you, Simon son of Jonah, for this was not revealed to you by flesh and blood, but by my Father in heaven. And I tell you that you are Peter, and on this rock I will build my church, and the gates of Hades will not overcome it. I will give you the keys of the kingdom of heaven; whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven.” Here, Simon’s name was changed to Peter (Cephas in Greek which means Rock) who was given the key of the kingdom of heaven with the power of binding and loosening. He was called to feed the sheep (cf. John 21:15-17) and strengthen his brethren in faith (cf. Luke 22:31-32).
And what is this kingdom of heaven that Peter has the dominion over? In Daniel 2:44, it was prophesied: “In the time of those kings, the God of heaven will set up a kingdom that will never be destroyed, nor will it be left to another people. It will crush all those kingdoms and bring them to an end, but it will itself endure forever.” This kingdom is the Church which was established by Christ upon the apostles during the existence of the Roman Empire. The Church herself endures forever, even the gates of hell shall not prevail (cf. Matthew 16:18).
Indeed, the authority of Peter and his successor, the Pope, has been prophesied long before the coming of the Christ in flesh. The fulfillment of the prophecy fell unto him, the man whom Jesus Christ, our God, exalted. He is the father in robe and sash ruling from a firm place. What is this firm place? This is where the Church is — the kingdom that destroyed the Roman Empire as prophesied in Daniel 2:44. The Roman imperial power started to decline when Christianity was freed from persecution as the result of the issuance of the Edict of Milan in A.D. 313 by Constantine I. All these happened in the church of Rome. Where is it? It is in the Vatican City as foretold in Matthew 5:14 — “You are the light of the world. A city set on a hill cannot be hidden.” Now, the Vatican City is an independent state which sets on the Vatican hill.
Lastly, the term Pope came from the Greek word “pappas” which means “father”. Historically, this title was applied, especially in the east, to all bishops in the early centuries of Christianity, and later became reserved in the west to the Bishop of Rome, a reservation made official only in 1075 by Pope Gregory VII. The earliest record of the use of this title was in regard to the by then deceased Patriarch of Alexandria, Pope Heraclas (AD 232–248). Meanwhile, the earliest recorded use of the title “pope” in English dates to the mid-10th century, when it was used in reference to Pope Vitalian in an Old English translation of Venerable Bede’s Historia Ecclesiastica Gentis Anglorum.
To reject the authority of the Pope, the anti-Catholics quoted 1 Corinthians 12:27-29 and Ephesians 4:11-12 stating that the early Church established only the offices of the apostles, prophets, evangelists, pastors, and teachers but not of the pope. Well, they just interpreted those biblical passages in the manner that would benefit them and their false claim. If those verses contadict the papacy just because the very term wasn’t listed in there, then it should also follow that the office of a bishop too was never established with apostolic origin. Of course, that is not true. The bishop, though not terminologically written in those given verses, is biblical as written in 1 Timothy 3:1, which reads: “This is a faithful saying: If a man desires the position of a bishop, he desires a good work.” See? The absence of just a term in one to two verses does not invalidate the reality. Indeed, the office of a bishop exists and the Pope is the Bishop of Rome who is both a pastor and a teacher.
Nevertheless, even though the term Pope only came to be used in the 11th century, the office of the Bishop of Rome has already existed in the earliest years of the Christian faith. In fact, in his book Against the Heresies, Irenaeus, bishop of Lugdunum in Gaul, wrote in AD 189: “To this Clement, Evaristus succeeded . . . and now, in the twelfth place after the apostles, the lot of the episcopate [of Rome] has fallen to Eleutherius.” This is clearly supported in the book Disputation with Proclus, the work of Gaius, a Roman jurist who lived from AD 110 to 179, stating: “It is recorded that Paul was beheaded in Rome itself, and Peter, likewise, was crucified, during the reign [of the Emperor Nero]. The account is confirmed by the names of Peter and Paul over the cemeteries there, which remain to the present time. And it is confirmed also by a stalwart man of the Church, Gaius by name, who lived in the time of Zephyrinus, bishop of Rome” (Eusebius of Caesarea, Ecclesiastical History 2:25:5).