What is the rock that Jesus will build his church on?
The RCC points to Peter...
Peter is a rock just like all of the apostles are "rocks", The rock, or foundation, or "cornerstone" is God/Jesus and that has ALWAYS been the case.
To believe the Catholic Church is to believe that Moses was referring to the yet-to-come Peter as being "perfect".
Deuteronomy 32:4
“
The Rock, his work is perfect,
for all his ways are justice.
A God of faithfulness and without iniquity,
just and upright is he.
And while we're at it...
Matthew 16:18 Young’s Literal Translation
And I also say to thee, that thou art a rock, and upon this rock I will build my assembly, and gates of Hades shall not prevail against it
You’ll note that Peter is referred to by Jesus as “a” rock and not the rock.
1 Samuel 2:2 ESV
“There is none holy like the Lord: for there is none besides you;
there is no rock like our God.
2 Samuel 22:2
He said, “The Lord is my
rock and my fortress and my deliverer,
Psalm 62:6 ESV
He only is my
rock and my salvation, my fortress; I shall not be shaken.
Psalm 144:1 ESV
Of David. Blessed be the Lord, my
rock, who trains my hands for war, and my fingers for battle;
1 Corinthians 10:1-4 ESV
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 that followed them, and
the Rock was Christ.
Psalm 18:46 ESV
The Lord lives, and blessed be my
rock, and exalted be the God of my salvation—
Matthew 7:24-25 ESV
“Everyone then who hears these words of mine and does them will be like a wise man who built his house
on the rock. And the rain fell, and the floods came, and the winds blew and beat on that house, but it did not fall, because
it had been founded on the rock.
Psalm 19:14 ESV
Let the words of my mouth and the meditation of my heart be acceptable in your sight,
O Lord, my rock and my redeemer.
1 Peter 2:7-9 ESV
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 of offense.” They stumble because they disobey the word, as they were destined to do. But you are a chosen race, a royal priesthood, a holy nation, a people for his own possession, that you may proclaim the excellencies of him who called you out of darkness into his marvelous light.
Isaiah 26:4 ESV
Trust in the Lord forever, for the Lord
God is an everlasting rock.
Psalm 18:1-2 ESV
To the choirmaster. A Psalm of David, the servant of the Lord, who addressed the words of this song to the Lord on the day when the Lord delivered him from the hand of all his enemies, and from the hand of Saul. He said: I love you, O Lord, my strength.
The Lord is my rock and my fortress and my deliverer, my God, my rock, in whom I take refuge, my shield, and the horn of my salvation, my stronghold.
1 Corinthians 3:11-16 ESV
For
no one can lay a foundation other than that which is laid, which is Jesus Christ. Now if anyone builds on the foundation with gold, silver, precious stones, wood, hay, straw— each one's work will become manifest, for the Day will disclose it, because it will be revealed by fire, and the fire will test what sort of work each one has done. If the work that anyone has built on the foundation survives, he will receive a reward. If anyone's work is burned up, he will suffer loss, though he himself will be saved, but only as through fire.
Isaiah 51:1 ESV
“Listen to me, you who pursue righteousness, you who seek the Lord:
look to the rock from which you were hewn, and to the quarry from which you were dug.
Psalm 61:1-3 ESV
To the choirmaster: with stringed instruments. Of David. Hear my cry, O God, listen to my prayer; from the end of the earth I call to you when my heart is faint.
Lead me to the rock that is higher than I, for you have been my refuge, a strong tower against the enemy.
Acts 4:11-13 ESV
This
Jesus is the stone that was rejected by you, the builders, which has become the cornerstone.
(Note: It's interesting to me that the verse in Acts 4:11-13 refers to Jesus as a "stone" rather than a rock).
1Peter 2:4
As you come to him, a living stone rejected by men but in the sight of God chosen and precious, 5
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. 6 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.”