Updated: May 22, 2022
By Luke Lancaster
Catholics frequently point to Matthew 16:19 as evidence for the office of the papacy. This is the case because of the background to Matthew 16:19. According to numerous Protestant bible scholars (see here and here), Jesus gave the keys of the Kingdom to Peter in order to allude to the Davidic Kingdom's office of Prime Minister. Such scholars connect Isaiah 22:22 with Matthew 16:19. In Isaiah 22:22, the Prime Minister Eliakim held the keys to King Hezekiah's Kingdom of Israel as a chief of staff figure. Eliakim was the King's vicar. If Jesus was the new Davidic King, then He would be like Hezekiah. David Stern pointed this out, showing that the Jews in the first century connected Hezekiah with the Messiah in his Jewish New Testament Commentary. This would then connect Eliakim with Peter.
But what is the history of connecting Isaiah 22 and Matthew 16? Is this a totally new interpretation? Although recent Protestant scholars have argued for it, the Catholic Church has had various members throughout Her history connect the two passages together.
St. Ephraim the Syrian
The first person to connect Isaiah 22 and Matthew 16 is St. Ephraim the Syrian (350 AD). Michael Aquilina, an expert on the Church Fathers, pointed out this quote of Ephraim's on his website (click here to see it). Ephraim does not explicitly say "Isaiah 22 connects with Matthew 16" but rather utilizes the vocabulary of Isaiah 22 when discussing Peter.
“Therefore the former Steward and the last Treasurer handed on the keys of the priesthood and prophecy to him [Jesus] who had authority over the treasury of both of these. Because of this his Father gave him the Spirit without measure, because all the measures of the Spirit are under his hand. And our Lord, to show that he had received the keys from the former steward, said to Simon [Peter]: To thee will I give the keys of the gates [Matt. 16:19]. But how could he give them to another unless he had received them from another? The keys, therefore, which he received from Simeon the priest, he gave to ‘Simeon’ the Apostle [Peter], so that even if the Nation would not listen to the former Simeon, the Nations should listen to the other ‘Simeon [Peter].’”
St. Ephraim speaks of the office of "steward" possessing "keys," which is exactly the office spoken of in Isaiah 22:15, 22. He continues by implying that these keys were passed down all the way to the first century Jewish holder, Simeon the priest. This man is called the "former Steward." From Simeon the priest, they were transferred to Jesus, who was filled with the Holy Spirit. Jesus then showed that He had the keys (Rev. 3:7) by giving them to Peter. This all implies that the new steward is Peter, and as seen in history, he passed on those keys to his successors in Rome.
St. John Cassian
The next person to connect Matthew 16 with Isaiah 22 is St. John Cassian (360-435 AD). Like St. Ephraim, he also does not explicitly connect Mt. 16 with Is. 22, but he does utilize the vocabulary of Is. 22:22 to indirectly allude to the office of Prime Minister. St. John Cassian says this in his description of St. Peter, saying,
“[Let us consult the] greatest of disciples among disciples, and of teachers among teachers, who presided and ruled over the Roman Church, and held the chief place in the priesthood as he did in the faith. Tell us then, tell us, we pray, O Peter, you chief of Apostles, tell us how the Churches ought to believe in God. For it is right that you should teach us, as you were taught by the Lord, and that you should open to us the gate, of which you received the key. Shut out all those who try to overthrow the heavenly house: and those who are endeavouring to enter by secret holes and unlawful approaches: as it is clear that none can enter the gate of the kingdom save one to whom the key bestowed on the Churches is revealed by you.” (Against the Nestorians on the Incarnation, book 3, chapter 12).
Notice the vocabulary from Isaiah 22:22. St. John Cassian speaks of Peter's ability to “open” and “shut” the “gate,” his possession of the singular “key” (Mt. 16 says “keys”), and the heavenly “house.” This connects with Isaiah 22:22’s reference to the ability of Eliakim to “open” and “shut” the gates. It also connects with the singular “key” of the “house of David” spoken of in Is. 22:22. Mt. 16:19 refers to the plural “keys,” whereas Is. 22 refers to the singular “key,” which is why St. John Cassian only uses the singular. He was naturally recalling Is. 22 in connection with St. Peter.
Following these Church Fathers, the writer named “Oecumenius” around the 500's AD explicitly connected Mt. 16 with Is. 22. He did so in his commentary on the book of Revelation. In Rev. 3:7, Jesus is said to possess the “key” of the house of David from Isaiah 22:22. Jesus explicitly quotes Isaiah 22:22, so this is no allusion. Oecumenius then says that Peter was given this key, which implies that Peter was given the office as well. He says,
“He [Jesus] calls authority a key. For he who has been entrusted with the key of the house has been entrusted with the authority to open and shut. And he more clearly stated this in the gospels in the promises to Peter” (Patristic Bible Commentary; cf. Greek Commentaries on Revelation).
This is a very explicit connection between Mt. 16 and Is. 22.
At this point, the next group of people to connect Is. 22 with Mt. 16 are in the 16th century. There probably are others in between the 500's and 1500's that did so, but I do not have access to them.
Cardinal Cajetan. He was sent to respond to the stir that Luther was causing in Germany, and said in 1521 that the Pope had authority because he was the possessor of Christ's keys. According to Cajetan, these "keys" Christ mentions giving to Peter in Mt. 16 were referencing the lines of Is. 22:22, where Eliakim held the keys to the Davidic Kingdom. See the book, Cajetan Responds: A Reader in Reformation Controversy (Catholic University of America Press, 1978, edited and trans. Jered Wicks, p. 115).
St. Francis de Sales. He was sent to the Calvinists in France to attempt to bring the followers of Luther back into the Catholic Church. He had great success, converting as many as 30-70k people! One of the main ways he did this was through pamphlets he wrote, which were later collected and compiled into a book. He wrote about the papacy in one of his tracts, and emphasized that Christ gave the keys of His Kingdom on earth to Peter, which was putting him in the position of Prime Minister like Eliakim in Isaiah 22:22. See the book, The Catholic Controvery (TAN publishers, 1989, trans. Henry Mackey, pgs. 254-255).
Cornelius Lapide. Cornelius was a Jesuit Scripture scholar that wrote extensive commentaries on the Sacred Page. A contemporary of St. Robert Bellarmine, Cornelius was very interested in converting the followers of Luther back into Christ's Church. So, when commenting on Matthew 16, Cornelius connects the keys of the Kingdom with Isaiah 22:22, indicating that Christ had the position of Prime Minister in mind. See the book, The Great Commentary of Cornelius Lapide (John Hodges publishing, 1893, trans. Thomas Mossman, 4th edition, Volume 2, p. 225).
St. Robert Bellarmine (AD 1542-1621). Edmund Gibson, an English Protestant bishop who argued against Bellarmine's defense of Catholicism, said that Bellarmine argued for the connection between Is. 22 and Matt 16. See A Preservative Against Popery in several Select Discourses upon the Principal Heads of Controversy between Protestants and Papists, being written and published by the most eminent divines of the Church of England, Chiefly in the Reign of King James II [1685-1688], (London, 1848), vol. 3, pgs. 17-18.
Besides these seven authors from Catholic history, the Roman Lectionary lines up Isaiah 22 and Matthew 16 together for the Mass readings in the twenty-first week of year A.
As we have seen, this interpretation of Matthew 16 and Isaiah 22 has a solid tradition behind it. Most biblical scholars today believe Jesus was referring to Isaiah 22 when giving Peter the keys, and some like to claim that this is a totally new interpretation. But as we have seen, they are not pointing out something new. Catholicism has used this powerful argument to support the office of the papacy for at least the last 1700 years. The Church Fathers and the opponents of Protestantism naturally saw the Is. 22 and Mt. 16 belonged together.