Thomas Aquinas Commentary Matthew 16:13-19

"Now when Jesus came into the parts of Caesarea Philippi, he asked his disciples, saying, Who do men say that the Son of man is? And they said, Some [say] John the Baptist; some, Elijah; and others, Jeremiah, or one of the prophets. He saith unto them, But who say ye that I am? And Simon Peter answered and said, Thou art the Christ, the Son of the living God. And Jesus answered and said unto him, Blessed art thou, Simon Bar-jonah: for flesh and blood hath not revealed it unto thee, but my Father who is in heaven. And I also say unto thee, that thou art Peter, and upon this rock I will build my church; and the gates of Hades shall not prevail against it. I will give unto thee the keys of the kingdom of heaven: and whatsoever thou shalt bind on earth shall be bound in heaven; and whatsoever thou shalt loose on earth shall be loosed in heaven." — Matthew 16:13-19 (ASV)

Above, the Lord taught that the Gospel teaching ought to be kept pure from the leaven of the Jews; now here He teaches the exalted nature of His doctrine.

He teaches this in three main ways:

1. Firstly, regarding faith in His two natures, His divine and human natures.
2. Secondly, regarding faith in His Passion, where it is said, From that time Jesus began to show to his disciples, etc.
3. Thirdly, regarding His judicial power, where it is said, For the Son of man shall come in the glory of his Father.

Concerning the first point—faith in His two natures—two aspects are explored:

1. The opinion of the multitudes about Christ is sought.
2. The disciples’ faith is sought, where it is said, But whom do you say that I am?

Regarding the opinion of the multitudes, three things are related:

1. Firstly, the place.
2. Secondly, Christ’s question, where it is said, Whom do men say that the Son of man is?
3. Thirdly, their reply, where it is said, But they said, etc.

Thus, the Evangelist says, Jesus came into the region of Caesarea; and he not only says this, but adds Philippi, because there were two Caesareas: Caesarea Palestinae, where Peter was sent to Cornelius, and this other Caesarea, which is also called Paneas. The first was established in honor of Caesar Augustus, and Philip constructed the latter in honor of Tiberius Caesar.

But why did the Lord ask this question here? It ought to be said that this city was located beyond the borders of the Jews; for that reason, before He chose to question them concerning their faith, He led them away from the Jews. Similarly, it is written that when the Lord led the Jews out of Egypt, He did not lead them out through the grain fields of the Philistines, as it is stated in Exodus 13.

Afterwards, the questioning is related: And he asked his disciples, etc. As Origen says, sometimes when a wise man asks, he teaches.

Thus, we are instructed in many things, so that we may be mindful of what is said about ourselves: if any ill is said about us, we are careful to correct it; if any good is said about us, we are careful to preserve and increase it. Therefore, it is written, Take care of a good name: for this will continue with you, more than a thousand treasures precious and great . For this reason, Christ asked what was being said about Himself.

Likewise, those who know His divinity are called gods—I have said: You are gods (Psalms 82:6)—but those who know His humanity are called men; hence, it is said: Whom do men say that the Son of man is? However, as Hilary says, Christ seemed to be merely a man, and for that reason, He wanted them to know that He is more than just a simple man. Thus, by this, He helps them understand that there is something else in Him.

Moreover, Christ’s humility is shown because He confesses that He is the Son of man, according to what is written: Learn of me, because I am meek, and humble of heart (Matthew 11:29).

Afterwards, the opinion of the multitudes is related: But they said: Some John the Baptist, etc. Different men thought different things about Christ. The Pharisees were blaspheming Christ, but the multitudes were saying that He was a prophet; for example: A great prophet is risen up among us, etc. (Luke 7:16).

They called Him John because of His counsel, for John preached penance: Do penance: for the kingdom of heaven is at hand (John 3:2). Therefore, they thought He was John, because Christ began in a similar way, saying, Do penance, for the kingdom of heaven is at hand (Matthew 4:17).

Likewise, they held the prophet Elijah in high esteem: Behold, I will send you Elijah the prophet, before the coming of the great and dreadful day (Malachi 4:5). Thus, they supposed He was Elijah on account of the power of His words and the force of His preaching: And Elijah the prophet stood up, as a fire, and his word burnt like a torch . And it was said concerning Christ that He was teaching them as one having power (Matthew 7:29).

Similarly, on account of the preeminence of His life, they supposed He was Jeremiah, concerning whom the Lord said: Before I formed you in the bowels of your mother, I knew you: and before you came forth out of the womb, I sanctified you (Jeremiah 1:5). And in the same place (Jeremiah chapter 40), it is stated that Jeremiah was honored by the Gentiles. In a similar way, Christ was held in esteem by foreigners, even though He was being blasphemed by the Jews; for that reason, they compared Him to Jeremiah.

But how is it that they were calling Him Elijah? It was because it is stated in 2 Kings 2 that Elijah was taken up, was still living, and was promised to the Jews for their salvation, as it is stated in Malachi 4. It was also because certain men thought that there is a transmigration of souls; and so, according to this opinion, it was possible that the soul of Elijah had entered into another body.

Jesus says to them: But whom do you say that I am? Here the disciples’ faith is investigated. This involves three parts:

1. Firstly, His question is related.
2. Secondly, the response is related, where it is said, Simon Peter answered.
3. Thirdly, His approval is related, where it is said, And Jesus answering, etc.

Jesus says to them: But whom do you say that I am? It is as if He were to say: ‘So say the multitudes; but because more has been committed to you, therefore, more is required from you. You have seen miracles; for that reason, you ought to reckon Me to be more than this.’

But why did He ask? Did He not know? He did indeed know, but He wanted them to merit by their confession: With the heart, we believe unto justice: but, with the mouth, confession is made unto salvation (Romans 10:10). Thus, things are more meritorious inasmuch as they are more outstanding; and it is as if the multitudes, because they knew the least about Christ, do not give any better reply about Him, and for that reason, etc.

Peter answered and said: You are Christ, the Son of the living God. He replies for himself and for the others; he replies more frequently, and in this his perfect faith is highlighted, because his faith in Christ’s humanity is mentioned. You are Christ, meaning ‘the anointed.’ And it is evident that He was anointed with the oil of the Holy Ghost. Anointing is not fitting for Him according to His divinity, because anointing proceeds from it, but it is fitting for Him according to His humanity. Therefore, Peter says this so that the disciples may esteem Christ’s humanity to be different than the multitudes esteem it to be.

Now the question arises why they were saying that He was a prophet. A prophet was anointed, as it is written concerning Elisha. Kings were anointed, as it is written concerning Saul; likewise, priests were anointed, as it is written in Leviticus. And all these roles were inferred in the name ‘Christ.’ This is because He is also called a king, as it is written: A king shall reign, and shall be wise (Jeremiah 23:5). Likewise, He is called a priest: You are a priest for ever according to the order of Melchizedek (Psalms 109:4). Again, He is called a prophet: The Lord your God will raise up for you a prophet from your nation and from your brethren, etc. (Deuteronomy 18:15).

Similarly, Peter not only confessed His humanity but, having penetrated the shell, he rises above it all the way to His divinity, saying, You are the Son of the living God. For others were calling Him a blasphemer; for instance: For a good work we do not stone you, but for blasphemy; and because you, being a man, make yourself God (John 10:33). But Peter recognized the Son of God.

And Peter says living to exclude the error of the Gentiles, who were calling dead men gods, such as Jupiter and others, as it is stated in Wisdom 13. Likewise, certain men called the elements and other dead things gods, such as the earth, fire, and so on, as it is stated in Wisdom 13; but he calls Him the Son of the living God.

But it should be known that when it is said ‘living God,’ and ‘living man,’ this is said of man through a participation in life; but it is said of God not by participation, because He is the source of life: For with you is the fountain of life (Psalms 35:10). And in John 14:6 it is said: I am the way, and the truth, and the life.

Jesus answering, etc. Here He does two things:

1. Firstly, He approves Peter's confession.
2. Secondly, He commands them to keep quiet, where it is said, Then he commanded his disciples, that they should tell no one that he was Jesus the Christ.

Regarding the first point (His approval), He approves the confession in two ways:

1. Firstly, by praising the one confessing.
2. Secondly, by His reward, where it is said, And I say to you: That you are Peter, etc.

Thus, the Evangelist says, Jesus answered: Blessed are you, Simon Bar-Jona. ‘Bar’ means ‘son of,’ and ‘Jona’ means ‘dove’ according to its name. Therefore, ‘Bar-Jona’ means ‘son of the dove.’ Christ’s reply seems to correspond to Peter’s confession. This is because Peter had confessed Him to be the Son of God; now Jesus calls him son of the dove, namely, of the Holy Ghost, because his confession could only be made by the Holy Ghost. However, it is thought that he was first called ‘Bar-Joannas,’ that is, the son of John, but this name appears due to an error in the text.

But what is this? Did not others confess that He is the Son of God? Indeed, it is so read of Nathanael in John 1. Likewise, those who were in the boat also confessed this (Matthew 14:33). Why, then, is Peter blessed here, and the others were not? It is because the others confessed Him to be an adopted son of God; here, however, Peter confesses Him to be the natural Son of God. For that reason, he is blessed here in preference to the others, because he was the first one to confess His divinity in this way.

Origen says: “It seems that he did not confess Him to be the Son of God before.” But how did Christ send them to preach? Origen answers that, at the beginning, they were not preaching that He was Christ, but they were merely preaching penance. Likewise, it may be that they were preaching that He is Christ, but this was the first time that Peter was confessing Him to be the Son of God in this specific manner. Therefore, Christ specially rewards him here.

Blessed are you, Simon, etc., because beatitude is in knowledge: Now this is eternal life: That they may know you, the only true God (John 17:3). But knowledge is twofold: one kind is by natural reason, and another is above reason. The first does not give beatitude, because it is doubtful and therefore does not satisfy the mind. Beatitude, however, ought to satisfy a natural desire, and this will be had in heaven: Eye has not seen, nor ear heard, what things God has prepared for those who love him (Isaiah 64:4). Therefore, in this life, inasmuch as a man can perceive more of this knowledge, he is more blessed: Blessed is the man that finds wisdom (Proverbs 3:13). Thus, He says, Blessed are you, meaning, ‘you begin to be blessed.’

Because flesh and blood has not revealed it to you. This can be expounded such that “flesh and blood” are taken to mean one’s human connections or earthly teachers, as in Galatians 1:16: Immediately I condescended not to flesh and blood. Thus: Flesh and blood has not revealed it to you; that is to say, you did not have this knowledge from the tradition of the Jews, but from a revelation of God.

Likewise, in Christ there were His flesh, blood, and divinity. Therefore, because Peter did not look to flesh and blood, it is said to Him, Blessed are you, because you do not judge according to what flesh and blood reveal, but according to what My Father reveals. Or, it means you do not have this knowledge from your own natural efforts, but from My Father. For no one knows the Son, but the Father (Luke 10:22). For it belongs to the One to make known, to whom it belongs to know. Thus, No one knew the Son except the one to whom the Father willed to reveal Him (Luke 10:22). There is a God in heaven that reveals mysteries (Daniel 2:28).

And I say to you: That you are Peter, etc. Here Christ gives the reward for Peter’s confession. Because Peter had confessed His humanity and divinity, the Lord gives him a reward. This reward has two parts:

1. Firstly, He gives him a name.
2. Secondly, He gives him power.

Concerning the first part of the reward (the name):

1. Firstly, He gives Peter his name.
2. Secondly, He gives the reason for the name, where it is said, And upon this rock I will build my church.

And for this purpose Christ came into this world: to found His Church. Behold I will lay a stone in the foundations of Zion, a tried stone, a cornerstone, a precious stone, founded in the foundation (Isaiah 28:16). This was signified by the stone that Jacob put under his head and anointed, as it is stated in Genesis 28. This stone is Christ, and from this anointing all Christians are called Christians; thus, we are not only called Christians from Christ, but also from the rock. For that reason, He specially names him: You are Peter, from the rock which is Christ.

Although, according to Augustine, it seems that this name was not given at this time, but was given at the beginning: You shall be called Cephas (John 1:42). Or it can be said that it was then promised, and it was here given. As a sign of this, it is said, upon this rock I will build my church. A distinctive characteristic of a rock is that it is placed in a foundation; likewise, another characteristic of a rock is that it gives firmness. He is likened to a wise man that built his house upon a rock (Matthew 7:24).

Thus, this can be explained as referring to Christ: And upon this rock, that is, Christ, so that He may be its foundation, and the Church, having been placed on this foundation, may gain firmness. Augustine, in his book of Retractions, says that this passage may be explained in multiple ways, and he left it to his listeners to adopt the explanation they prefer. For instance, this passage may be expounded such that the words this rock signify Christ: And the rock was Christ (1 Corinthians 10:4). And elsewhere, it is written: Another foundation no one can lay, but that which is laid: which is Christ Jesus (1 Corinthians 3:11). There is another exposition: Upon this rock, meaning upon you who are a rock, because you yourself draw from Me that you are a rock. And just as I am a rock, so upon you who are a rock I will build My Church, etc.

But what is this? Are both Christ and Peter the foundation? It must be answered that Christ, in Himself, is the foundation, but Peter is the foundation insofar as he confesses Christ and insofar as he is His vicar. Built upon the foundation of the apostles and prophets, Jesus Christ himself being the chief cornerstone, etc. (Ephesians 2:20). There are twelve foundations of the city: And in them, the twelve names of the twelve apostles of the Lamb (Revelation 21:14).

Christ, in Himself, is the foundation; but the Apostles are foundations as well—not in themselves, but through Christ’s delegation and through the authority given them by Christ: The foundations thereof are the holy mountains (Psalms 86:1). But Peter’s house especially, which was founded upon the rock, shall not be demolished, as said above in Matthew chapter 7. Thus, this house can be assaulted, but it cannot be conquered.

And the gates of hell shall not prevail against it. They shall fight against them, and shall not prevail (Jeremiah 1:19). And what are the gates of hell? They are the heretics: because just as one enters a house through a gate, so one enters into hell through these heretics. Likewise, the gates of hell are tyrants, devils, and sins.

And although other churches could be corrupted by heretics, nevertheless the Roman Church was not corrupted by heretics, because it was founded upon a rock. Thus, in Constantinople, there were heretics, and the labor of the Apostles was lost; only the Church of Peter remained inviolate. Therefore, it is written: I have prayed for you, Peter, that your faith may not fail (Luke 22:32). And this is not only ascribed to the Church of Peter but also to the faith of Peter, and to the whole Western Church. For this reason, I believe that the Western faithful ought to have more reverence for Peter than for the other Apostles.

And I will give to you the keys of the kingdom of heaven. Here the second gift is related which Christ, according to His humanity, gave to Peter. For He founded the Church in the world and appointed Peter to be His Vicar, so that Peter might give the Church entrance into heaven. Therefore, He gave him that ministry, and thus He gave him the keys. For a key gives entrance; therefore, Peter has the ministry of giving entrance. And Christ does two things:

1. Firstly, He entrusts the keys.
2. Secondly, He teaches their use, where it is said, And whatever you shall bind upon earth, it shall be bound also in heaven, etc.

But let us see what the keys are. A locked house prevents entrance, but a key removes this obstacle. The kingdom of heaven has an obstacle to entry, but the obstacle is not on its part—I looked, and behold a door was opened (Revelation 4:1)—rather, it is on our part, namely sin, because nothing defiled shall enter into it.

Christ removed these obstacles through His Passion, because He has washed us from our sins in his own blood (Revelation 1:5). And He shared this benefit with us so that, through Peter’s ministry, our sins are taken away. This is accomplished through the power of Christ’s blood; thus, the sacraments have power by virtue of Christ’s Passion. Therefore, He says, I will give to you the ministry, etc., and I will lay the keys of David upon you (Isaiah 22:22).

But He says, I will give to you, for the keys were not made yet, and a thing cannot be given before it exists. These keys were to be made in His Passion; thus, their efficacy was in the Passion. Therefore, here He promises to give the keys to Peter, but He gave them to him after the Passion, when He said: Feed my sheep (John 21:17).

But why does He say “keys” (plural)? It is because to absolve is to remove obstacles. For there are two obstacles, corresponding to two things that are required: namely, power and knowledge.

But what is this? Are there not some priests who do not have this knowledge? You could understand this statement to mean that they do have knowledge, because no one has the key of knowledge except a priest. However, what is called “knowledge” here is not intellectual learning or an acquired skill, etc., but rather the authority of discerning. Thus, a judge, for example, may not have knowledge in the first sense (intellectual learning) but nevertheless possess it in the second sense if he has the authority of discerning. Conversely, someone may have knowledge in the first sense but not in the second if he does not have authority. Therefore, the authority of discerning is what is called knowledge here, and any priest has this kind of knowledge so that he may discern in absolving.

Afterwards, He sets forth the use of the keys: Whatever you shall bind upon earth, it shall be bound also in heaven. But it seems that their use is not appropriately described, because the use of a key is not to bind but to open. I say that this is indeed a fitting description of the use of keys. For heaven was opened—I saw a door opened (Revelation 4:1). Thus, it is not necessary that heaven itself be opened further, but that a person who is bound, and who ought to enter heaven, should be loosed.

But here some errors should be avoided. These include:

1. The first, mentioned in the Gloss, is that some people wrongly assumed that priests are able to absolve everyone they choose to absolve and take them into heaven. But this cannot stand, because to change wills belongs to God alone.
2. Another error is that a priest does not absolve but merely declares that a person is absolved. This, however, takes away the power of the sacrament, because the sacraments of the New Law produce what they signify, whereas the sacraments of the Old Law do not. Thus, if nothing were produced, it would not be a sacrament of the New Law.
3. Thirdly, some people say that in sin there are three things: the guilt, the debt, and the punishment.

According to this third view, a person is absolved from two of these (guilt and debt) through contrition. However, when a person is absolved from these, they remain obliged to the temporal punishment, which a person is unable by themselves to remove and avoid. For that reason, they say, the keys are given, which lessen some of this punishment and bind to some punishment.

Nevertheless, it seems to me that this view is incorrect, because the sacraments of the New Law give grace, and grace is ordained to be a remedy not primarily for punishment, but for guilt.

Therefore, I say that it is thus in this sacrament of Confession, just as it is in the sacrament of Baptism, which has a spiritual instrumental power by which it cleanses from guilt.

Thus, Augustine says: “What is the power of water, that it washes the flesh and takes away guilt?” So I say that in the priest there is a spiritual instrumental power, by reason of which he is called a minister, and he ministerially effects the forgiveness of guilt, just as the water of Baptism does.

But the latter (Baptism) causes a difficulty, because in our time mostly children come to Baptism. If an adult comes forward to be baptized, they come either insincerely or sincerely. They come insincerely if they come without a renewal of their soul, and then sin is not forgiven. They come sincerely if they come with the intention of confessing their sins; thus, grace is required, or the intention of conversion, and this is from grace. Grace takes away guilt. Therefore, in the sacrament of Baptism, the adult coming forward, if they prepare themselves, receives the forgiveness of guilt. So too in the sacrament of Penance, to which only adults approach, one is not contrite unless one has the intention of subjecting oneself to the discernment and judgment of the priest.

If one is not contrite, the effect is not obtained, just as it would not be obtained in Baptism. But it can happen that someone not completely contrite approaches the sacrament of Penance, who, by the power of the grace conferred in this sacrament, is made contrite when it has been completed. For that reason, the words Whatever you shall loose should be understood to mean, ‘whatever you shall loose by administering absolution.’

And He says, Whatever, because the priest not only absolves from guilt but also from punishment. He says, Shall be loosed in heaven, meaning it will be accounted as absolved in heaven, just as it is concerning Baptism. Therefore, the priest ought to say, ‘I absolve you,’ just as he says, ‘I baptize you.’

But someone could inquire how the priest binds. It should be known that a priest is God’s minister, and the action of God’s minister depends upon the act of the Lord. Thus, in the same way that the Lord binds and looses, so the priest binds and looses ministerially. God looses by infusing grace and binds by not infusing grace; so the priest looses by the sacrament (by administering the sacrament) but binds by not administering the sacrament.

Alternatively, it is said that “heaven” here designates the present Church. Thus: Whatever you shall bind or loose (for example, by excommunication) shall be bound or loosed in regard to the administration of the sacraments of the Church. Consequently, some people maintain that this administration—this binding and loosing—is only upon earth, such that it does not extend to the dead.

But this view is condemned, because this power extends not only to the living but also to the dead. Therefore, if the administration of the sacraments is ascribed to both binding and loosing, the meaning is: Whatever you shall bind upon earth (that is, while you are dwelling upon earth), it shall be bound also in heaven.

It should be said that Christ immediately gave this power to Peter; but the other disciples receive this power from Peter. For that reason, lest it be supposed that these things were said only to Peter, He says to all the apostles: Whose sins you shall forgive, etc. (John 20:23). And for this reason, the Pope, who is in St. Peter’s place, has full power immediately from God, but the other Apostles have their power from him.