In Matthew 16:18 stands a well-known saying of the Lord Jesus: 

“And I tell you, you are Peter, and on this rock I will build my church, and the gates of hell shall not prevail against it.” (ESV) 

A play on words 

In the above translation the word “Peter” represents the Greek noun petros, which means “stone” or “rock.” 

And in the third clause of the sentence, “rock” is a translation of the Greek noun petra. 

In the Greek text of this verse, then, Jesus is making a kind of play on words: 

“. . . you are petros, and on this petra I will build my church . . .” 

And if we translate this play on words into English, we have: 

“. . . you are Rock, and on this rock I will build my church . . .” 

Many claim that the rock Jesus will build on is not Peter 

You will often hear Christian teachers say that in this verse the rock on which Jesus will build His church is not Peter. Many argue that if Matthew had meant that Jesus was going to build His church on Peter, he would have used the word petros twice in the saying, in this way: 

“. . . you are petros, and on this petros I will build my church . . .” 

The fact that the second word is petra instead of petros, so the argument goes, shows that Peter should not be identified as the rock on which Jesus will build His church. Those who argue in this way say that this rock is in fact Jesus, or perhaps Peter’s confession about Jesus, or something similar. 

Answering this claim 

At first sight this might seem to be a good argument. Nevertheless, there should in fact be no doubt that the rock on which the church is said to be built in this verse is Peter. The following two points are important: 

If Peter were not the rock, the saying would look strange 

First, if Peter were not the rock, the saying would look very strange. It would mean that Jesus begins by stating, “And I tell you, you are Peter,” but then moves on immediately to talk about something else, without giving any information about Peter. This seems very awkward. 

We can explain the presence of petra 

Second, it is easy to explain why petra has been used instead of a second petros. 

In the first century petros was almost never used as a common noun. It would therefore probably have made the Greek look odd, perhaps even absurd, if it was used in this way in this saying. By contrast, in the first century petra was often used as a common noun. 

Furthermore, even on those rare occasions when petros was used as a common noun, it may well have referred only to an isolated stone or rock rather than a foundation stone. If so, then for another reason it would have been inappropriate to use it in Jesus’ statement. By contrast, petra was often used to refer to a foundation stone. 

There are good reasons, then, for thinking that it was not really possible to have “on this petros” in the Greek of this saying. Instead Matthew seems to have chosen “on this petra” as the closest possible alternative that read well in Greek. 

Considering the underlying Aramaic 

Anyone who is involved in language translation will find that there are times when it is not possible to translate something perfectly from one language into another. And it seems that this is what happened with this saying. 

It is almost certain that the saying was first spoken not in Greek but in Aramaic. This was the everyday language of Jesus and of most of the very first Christians. 

In Aramaic the standard word for a stone or rock was kepha. And we know that this word was used by Aramaic-speaking Christians to refer to Peter. We find it as a name for him in John 1:42; 1 Corinthians 1:12; 3:22; 9:5; 15:5; Galatians 1:18; 2:9, 11, 14. English versions usually use the word “Cephas” in these verses, but this is simply the Anglicized form of the Greek word kephas, which is itself the Grecized form of the Aramaic kepha. 

So we know that the word kepha, meaning “rock,” was used to refer to Peter. And this means that in the original Aramaic of the saying, kepha would surely have been used to refer to him, as follows: 

“. . . you are kepha . . .” 

But let’s do a little thought experiment now. Let’s suppose that in the original Aramaic of the saying, kepha was used not only to refer to Peter but also to the rock on which the church would be built, as follows: 

“. . . you are kepha, and on this kepha I will build my church . . .” 

Now, to continue our experiment, we need to try putting ourselves in the shoes of a first century Christian who is translating this as naturally as they can into Greek: 

To begin with, Peter was already known in Greek by the word petros, so this would surely have been chosen to translate the first kepha: 

“. . . you are petros . . .” 

But what about the second kepha in the saying? What is the most natural way of translating this into Greek? 

It seems that in the Greek of the first century there were three words meaning “stone” or “rock,” which could potentially have been used to translate the second kepha. These words are petros, lithos and petra. Let’s think about each of these in turn: 

(1) I noted above that petros was an extremely rare word and that it may well have been unsuitable as a reference to a foundation stone. So it is easy to see why this word would not have been used to translate the second kepha. 

(2) Lithos was a common word in the first century. However, this too may have been unsuitable as a reference to a foundation stone. Furthermore, even if it could be used to refer to a foundation, lithos sounds very different from petros, meaning that the repetition of kepha in our hypothetical Aramaic would not be reproduced at all well in Greek: 

“. . . you are petros, and on this lithos I will build my church . . .” 

Note how the repetition of sound is lost in this translation. 

(3) As far as petra is concerned, I have already noted that this word was common in the first century, and that it was used to refer to a foundation stone. Furthermore, it sounds very similar to petros, so the repetition of kepha in our hypothetical Aramaic would be reproduced quite well by using petra: 

“. . . you are petros, and on this petra I will build my church . . .” 

It seems, then, that if the original Aramaic of the saying used the word kepha twice, petra is the best Greek word to translate the second kepha. And when we do translate this with petra, the resulting Greek text is exactly what we have in Matthew 16:18: 

“. . . you are petros, and on this petra I will build my church . . .” 

In other words, if we posit that the original Aramaic used kepha to refer both to Peter and to the rock on which the church would be built, the most natural way of translating this into Greek is exactly what we have in the Greek text of Matthew 16:18. 

So our Greek text of Matthew 16:18 is exactly what we would expect to have come from an Aramaic original that said: 

“. . . you are kepha, and on this kepha I will build my church . . .” 

And if kepha was repeated in the original in this way, because the first kepha certainly refers to Peter, the second surely does too. In other words, if kepha was repeated in the original, Jesus would surely be saying that He would build his church on Peter. 

A consideration of the underlying Aramaic of this saying, then, helps support the conclusion above that Peter is the rock on which Jesus would build His church. 

This verse is often very badly interpreted 

Matthew 16:18 has probably been one of the most badly interpreted Bible verses in the history of the church. 

On the one hand, Roman Catholics have used this verse to support their doctrine of papal succession. They argue that the church being built on Peter refers, in part at least, to the line of popes following on from each other. 

This, however, is to read something into the text that is simply not there. 

On the other hand, the most common interpretation in evangelical circles denies that Peter is the rock on which the church is built. 

As I argued above, however, this is a misinterpretation. 

Part of the motivation for evangelicals to interpret in this way is undoubtedly to try to undermine Catholic use of this verse. It seems that many evangelicals think that if they can persuade people that Peter is not the rock, they will have removed one reason for believing in papal succession. 

It is good to want to oppose belief in papal succession. Nevertheless, it is never right to misinterpret the Bible, even when this is motivated by a desire to counter false teaching. Difficulties need to be faced and addressed honestly. 

Interpreting this verse 

As it happens, it is possible both to reject Catholic claims and to be honest with the text here. 

I have already noted that there is no support in this verse for the doctrine of papal succession. 

Importantly too, it is not necessary to think that the verse is telling us that Peter is a foundation of the church in some precise, technical sense. Modern Western interpreters often get caught out by taking biblical expressions too technically. However, Jesus’ statement here is better understood simply as a vivid illustration of how much He would use Peter in the first years of the church. We could paraphrase His words in this way: 

“Peter, I am going to use you massively in the early stages of building my church.” 

That seems to be what this saying is about. There is no need to take it any more technically than that. 

Learning from Peter’s life 

A few years before Jesus spoke these words Peter was probably contemplating living out his days as a fisherman on the Sea of Galilee. He almost certainly had no idea that God had singled him out for a hugely important role in His plan for the world. 

We know too that this same Peter was someone who sinned badly against Jesus by denying Him (Matthew 26:69-75 etc.), despite his promise that he would remain with Him to the end (Matthew 26:31-35 etc.). 

However, neither Peter’s ordinariness nor this sin stopped the Lord using him. Jesus kept His promise and used Peter greatly in building His church, as the book of Acts tells us. 

There are lessons here for Christians today. 

If you feel that there is nothing exceptional about you, don’t rule out that God may have special purposes for you that you haven’t even dreamed of. Maybe He wants to use you greatly in building His church too. 

And don’t think that entertaining such a thought would be to lack humility. That wouldn’t be true at all. God does use some people greatly. So why can it not be you? 

Or maybe you have sinned badly in some way. If so, then look at what happened to Peter. He repented, and God forgave Him and then took him forward from that point. 

Don’t let past sins prevent you from being used by the Lord in the future. Peter didn’t and he went on to do great things for Him.

See also: 

Beware of Becoming Attached to Church Traditions 

Christians Need to Put Everything to the Test

I have been a Christian for over 30 years.  I have a Ph.D. in New Testament from the University of Edinburgh.  I am a UK national and I currently live in the south of Scotland.  Check out my blog, The Orthotometist, at maxaplin.blogspot.com