One of the most controversial passages in
the Bible is Matthew 16:18, where Jesus tells Peter, “You are Peter, and on this rock I
will build my Church.” Catholics see this passage as evidence that
Jesus made Peter the first pope. Many Evangelicals look at it as just the opposite.
Who is right? It’s an interesting question, and I’ve been
on both sides of the question. In fact, this passage played a pivotal role in my conversion
to the Catholic Church. You may think you’ve heard all the arguments
about whether Peter is the rock, but I’m going to show you the one that convinced me, and
you probably haven’t heard it anywhere else . . .
The Basic Argument
A common claim in Protestant apologetics is that in Matthew 16:18, Jesus is actually contrasting
St. Peter with the rock on which he will build his Church.
The argument is based on the fact that in Greek the word for Peter is petros, while
the word used for “rock” here is petra. It is often claimed that these words meant
two different things–that petros meant a small stone or a pebble, while petra meant
a large rock. The idea is that Jesus is contrasting Peter–a
tiny, insignificant stone–with the great rock on which he will build his Church, which
is often said not to be Peter but Peter’s faith.
How well does this argument work?
Small Stone vs. Large Rock? In the Expositor’s Bible Commentary, the esteemed
Evangelical Bible scholar D. A. Carson writes on this passage:
Although it is true that petros and petra can mean “stone” and “rock” respectively in earlier
Greek, the distinction is largely confined to poetry.
Moreover the underlying Aramaic in this case is unquestionable; and most probably kepha was
used in both clauses (“you are kepha and on this kepha”), since the word was used both
for a name and for “rock.” The Peshitta (written in Syriac, a language
cognate with Aramaic) makes no distinction between the words in the two clauses.
The Greek makes the distinction between petros and petra simply because it is trying to preserve
the pun, and in Greek the feminine petra could not very well serve as a masculine name.
So the argument that petros and petra have different meanings in this passage is actually
quite weak. But for the sake of argument, let’s suppose
that they did. Would this mean that Peter isn’t the rock?
You May Look Small . . .
The argument that he isn’t is based on the fact that there is a clear parallelism between
Peter and the rock in this passage, and it assumes a particular kind of parallelism–one
that contrasts Peter with the rock. This is sometimes called antithetic parallelism.
But that isn’t the only kind of parallelism there is. The Bible often uses another form,
known as synthetic parallelism. In synthetic parallelism, the second item
mentioned builds on or amplifies the meaning of the first.
If that’s what’s happening in this passage–even if we grant that petros means a small stone
and petra means a large rock–then it does not follow that Peter and the rock are two
different things. Instead, Jesus would be saying something like,
“Although you may seem to be a small stone, Peter, on the large rock that you really are,
I will build my Church.” In this case petra or large rock would bring
out the actual significance of the small stone that Peter appears to be.
But there are even more decisive arguments, and you don’t have to speak Greek or Aramaic
to understand them . . .
My Own Conversion A key moment in my own conversion occurred
one day when I was reading a book, and it had an extended quotation from Matthew 16.
I suddenly realized that there was a structural feature in the text that pointed to Peter
being the rock. Soon afterward, I noticed additional features
that indicated the same thing. I realized that these were far stronger indicators
than the arguments I had previously taken for granted regarding the alleged difference
in meaning between petros and petra, and I had to change my view.
Here is what I discovered . . .
Jesus Asks a Question If we back up a few verses, we find Jesus
asking the disciples a question:  Now when Jesus came into the district
of Caesare’a Philip’pi, he asked his disciples, “Who do men say that the Son of man is?” 
And they said, “Some say John the Baptist, others say Eli’jah, and others Jeremiah or
one of the prophets.”  He said to them, “But who do you say that I am?”  Simon
Peter replied, “You are the Christ, the Son of the living God.”
That’s the correct answer, and Jesus says three things to Peter in reply:
 And Jesus answered him, “Blessed are you, Simon Bar-Jona! For flesh and blood has
not revealed this to you, but my Father who is in heaven.  And I tell you, you are
Peter, and on this rock I will build my church, and the gates of hades shall not prevail against
it.  I will give you the keys of the kingdom of heaven, and whatever you bind on
earth shall be bound in heaven, and whatever you loose on earth shall be loosed in heaven.”
What I noticed was that there are structural features in Jesus’ three statements to Peter
that indicate he is the rock.
Blessed Are You One thing I noticed is that the statements
immediately before and after the “You are Peter” passage are both blessings.
First, Jesus says “Blessed are you, Simon Bar-Jona!” That is clearly a blessing.
Then he says, “You are Peter.” And finally he says, “I will give you the
keys to the kingdom of heaven.” That also is clearly a blessing.
So “You are Peter” is sandwiched between two blessings. The passage unambiguously stresses
the blessedness of St. Peter. That argues against the idea that Jesus is
belittling Peter in this passage. It would be like Jesus saying, “Blessed are
you, Simon Bar-Jona! . . . You insignificant pebble. . . . Here are the keys to the kingdom
What It Means to Be Peter I also noticed that each of Jesus’ three statements
to St. Peter has a two-part explanation attached to it.
The first statement, “Blessed are you, Simon Bar-Jona!” is explained by “For flesh and
blood has not revealed this to you,” which is then further explained by “but my Father
who is in heaven.” These are why Peter is blessed. He didn’t
learn of Jesus’ identity from man. It was revealed to him by the Father.
The third statement, “I will give you the keys of the kingdom of heaven,” is explained by
“and whatever you bind on earth shall be bound in heaven,” which is then further explained
by “and whatever you loose on earth shall be loosed in heaven.”
These are part of what it means for Peter to have the keys of the kingdom. He is able
to bind things with authority from God, and he is able to loose things with authority
from God. So when it turns out that the second, or middle
statement also has the same structure, then we need to read it in the same way.
The statement “you are Peter,” is explained by “and on this rock I will build my church,”
which is further explained by “and the gates of hades shall not prevail against it.”
So that is what it means for him to be Peter: Jesus will build his Church on him, and the
gates of hades will not prevail against it.
What This Means for Us When I realized these things, I realized that
Peter had to be the rock Jesus was talking about. And that was a pivotal moment in my
journey with God. Because if Peter is the rock on which Jesus
builds his Church, that means that Peter is the chief apostle, the chief shepherd of Christ’s
flock. And that means that, once Jesus has ascended to heaven, Peter is the earthly head
of the Church. That’s a good description of the office of
the pope. And so, when I realized these things, I concluded
that I had to reconsider matters. I had to review my beliefs with an open mind toward
whether the Catholic Church was right after all.
In the end, I concluded that it is, and so I became Catholic.
In the years since, my conviction has only strengthened as I have learned more about
Catholic teaching and its basis in the Bible, including the role of the pope.