Well, as Roman Catholics define "this rock" to be Peter, then a lot of people are going to be in for a surprise.
Then the Catholic church is built on the wrong rock.
The Rock that the church I'm part of is built on JESUS CHRIST.
Here, Paul identifies who petra is, and that is Christ. This link takes you to the Greek.
http://biblehub.com/text/1_corinthians/10-4.htm
1 Corinthians 10:1-4 For I do not want you to be unaware, brothers, that our fathers were all under the cloud, and all passed through the sea, and all were baptized into Moses in the cloud and in the sea, and all ate the same spiritual food, and all drank the same spiritual drink. For they drank from the spiritual Rock (petra) that followed them, and the Rock (petra) was Christ.
http://biblehub.com/text/romans/9-33.htm
Romans 9:30-33 What shall we say, then? That Gentiles who did not pursue righteousness have attained it, that is, a righteousness that is by faith; but that Israel who pursued a law that would lead to righteousness did not succeed in reaching that law. Why? Because they did not pursue it by faith, but as if it were based on works. They have stumbled over the stumbling stone, as it is written,“Behold, I am laying in Zion a stone of stumbling, and a rock (petra) of offense; and whoever believes in him will not be put to shame.”
http://biblehub.com/text/1_peter/2-8.htm
1 Peter 2:1-8 So put away all malice and all deceit and hypocrisy and envy and all slander. Like newborn infants, long for the pure spiritual milk, that by it you may grow up into salvation— if indeed you have tasted that the Lord is good.
As you come to him, a living stone rejected by men but in the sight of God chosen and precious, you yourselves like living stones are being built up as a spiritual house, to be a holy priesthood, to offer spiritual sacrifices acceptable to God through Jesus Christ. For it stands in Scripture: “Behold, I am laying in Zion a stone, a cornerstone chosen and precious, and whoever believes in him will not be put to shame.”
So the honor is for you who believe, but for those who do not believe,
“The stone that the builders rejected has become the cornerstone,”
and
“A stone of stumbling, and a rock (petra) of offense.”
They stumble because they disobey the word, as they were destined to do.
All occurrences of *petra* in the Greek.
They didn't USED to!!
What changed?