An important verse cited by Roman Catholicism in support of the Papacy is Matthew 16:18: "And I tell you, you are Peter and on this Rock I will build my Church, and the powers of death shall not prevail against it."

Many Protestants in the past, in order to avoid identifying Peter as the rock, have tried their hardest to impose their own beliefs on this verse as they do with the rest of the Holy Scripture when it doesn't agree with their opinion. Some say Jesus was speaking of Himself or of Peter's confession of faith on which He would build His church. There are still some who cleave to this erroneous interpretation based solely not on an honest love of and obedience to Christ and His word, but on their own doctrine of "sola ego".

As we enter the 3rd millennium though, nearly every major Protestant commentary agrees that Jesus was referring to Peter himself as the rock He will build his church on. (New American Commentary, The Anchor Bible, Bible Students' Commentary, Tyndale New Testament Commentaries.. to name a few.) The next logical step to follow would be acknowledging his successors. Let's hope that it doesn't take Protestants another 400 years to realize this truth.

Now, for those few who still hold to the former belief and for the benefit of all who wish simply to understand the Papacy better, I will discuss this verse more thoroughly.
The most widely populated attempt to refute the Catholic interpretation of this verse deals with the Greek text, specifically with the words Petros and Petra. When we read Matt16:18 using these words, it would read as such: And I tell you, you are Petros and on this Petra I will build my Church, and the powers of death shall not prevail against it.

This statement can be interpreted two ways but only one is grammatically correct. Do you think I meant that Peter was told by Jesus that Jesus himself was a tiny pebble? Of course not! The noun "Peter" closest to the pronoun "he" would be the correct understanding of who was meant. This rule also applies to the verse of Scripture we're looking at. The phrase "this rock" must be associated with the closest noun "Peter". Peter's profession of faith was two verses before this so it couldn't be referring to this. And the nearest we find Jesus' name mentioned is in this same verse, two verses before. So the only rock Jesus was referring to was Peter!

For the second case against this argument, we must look at a few verses extra, Matthew 16:17-19, the ones surrounding verse 18:

Now let's examine the actual Greek words, Petros and Petra. First of all, by the first century during which time Matthew's gospel was written, the words Petros and Petra were interchangeable. Petra doesn't always refer exclusively to a large rock. Just look at 1 Peter 2:8:

A stone(lithos) that will make people stumble, and a rock(petra) that will make people fall.

Here "petra" is understood by the context to mean a small stone which will make people trip, not a huge massive rock. Also, if Jesus really wanted to be clear about Simon Peter being a pebble, the Greek language has a distinct word for this as can be seen in the beginning of verse 8. (lithos = small stone)

Why isn't Petra used for Peter's name? First we must realize that Christ did not speak to his disciples in Greek. The common tongue of the time and the language Christ spoke was Aramaic. There is only one word for "rock" in Aramaic and that word is "kepha". How did we get "Petra" from "kepha"? When Jesus first met Simon, He looked at him and changed his name to Cephas (English transliteration of Greek Kephas which is from the Aramaic word Kepha). This can be seen in John 1:42:

He brought him to Jesus. Jesus looked at him, and said, "So you are Simon the son of John? You shall be called Cephas[Kephas]" (which means Peter{Petros})

If Jesus had wished to give Simon a name to signify a small stone, there were several words in Aramaic which he could have used..."evna" for example. What really proves that Petros is identical with 'rock' and not 'small stone' is first made apparent in the preceding verse, John 1:41:

He first found his brother Simon, and said to him, "We have found the Messias (which means Christ {Christos})"

By examining the speech used, we find the Aramaic word 'messias' being translated to mean the Greek word 'Christos'. In John 1:42 that we read before, we find the Aramaic word 'Kepha'{Kephas, Cephas} being translated into Greek as 'Petros'. What this means logically is that Cephas{Kepha} which only means 'rock' in Aramaic, is equal to the Greek word, 'Petros'.

Let's look at the new name Jesus calls Simon. But before we do this, let's examine what a name change in the bible meant. If you examine some examples you will realize that when God changes someone's name, he also designates new duties to that person. Notice the names God gives the angels which pertain to some quality they possess. In the Old Testament, God changes Abram's name to Abraham (Gen. 17:5) [see also Gen. 32:38, where Jacob's name is changed to Israel and 2 Kings 23:34, where Eliakim's name is changed to Joakim].

Abram in Hebrew means "exalted father". Abraham means "chief of the multitude". In the light of this, let us examine Isaiah 51:1-2:

In these verses, Abraham is referred to as "the rock from which you were hewn". Many Jewish rabbinical writings (Talmudic texts) as early as the 2nd century recognize this (Yalkut Shimoni: "a rock upon whom I can found a world"). Many Protestant commentaries also cite this. Now wait a minute, in Psalms 18:2, 31, and 46, God is called the rock and the same Hebrew word is used to designate Him as such... Sur.

See the connection! If the Jewish people were able to refer to Abraham as the "rock" when this word was also used when referring to God in the Old Testament, and as their father, why see the difficulty in saying that Peter was the rock in Matthew 16:18 and spiritual father to all? (Pope = papa = father)