Monocausalism and the Rock on which the Church is Built

St. Peter Holding the Key of Paradise
Pierre Puget (1653-1659)

From the Catholic point of view, Christ Himself is the cornerstone of the Church. Christ is one Person in two natures: one invisible, and one visible. So the Church (His Body) likewise has both aspects. It is both a visible organization and a spiritual community. (See CCC 771)

Although Christ is the head and chief cornerstone of the Church, during His absence [between the time of His ascension and the time of His return] He has entrusted the keys of His kingdom to His chief steward. (cf. Matthew 16:18-19, Luke 12:42) In other words, from a Catholic point of view, there is no contradiction between Christ being the head and cornerstone of the Church, and Peter also being a rock (subordinate to Christ) upon which Christ builds His Church, in the sense of making Peter its chief steward.

Often in Catholicism it is not an "either/or", but a "both/and". And the same is true of Matthew 16. But in Protestant contexts we quite commonly encounter the following dilemma: either the rock Jesus speaks of here is Peter or it is Peter's confession. But this is a *false* dilemma. The reason it is a false dilemma is that it is based on an implicit monocausalist assumption, i.e. that only one thing can be the rock on which the Church is built.

From a Catholic point of view there are at least four things the Church is built on: (1) Christ, who is the referent of Peter's confession of faith, (2) Peter the Rock, who makes the confession of faith, (3) the propositional content of Peter's confession, and (4) Peter's act of faith, for which He was commended by Christ, and given the keys by Christ. Each of these last three points to Christ. God the Father had revealed Christ's identity to Peter first, and this was a sign that Peter was to be the chief steward of the Kingdom, that is, the chief representative of Christ. The steward points to Christ because He is Christ's representative, the "vicar of Christ". The propositional content of Peter's confession obviously points to Christ, for Christ is what Peter's words were about. And Peter's act of faith points to Christ too, as an act of worship speaks about the worthiness of the recipient.

These last three are the three "bonds of unity" of the Church. (See CCC 815) I wrote about these in more detail under the section "The Three Modes of Organic Unity" here.

So the Catholic Church does not think it has to choose between Peter being the rock, and Peter's confession being the rock, and Peter's faith being the rock. They are all true, and they are all inseparable.

Here are some paragraphs from the Catholic Catechism that show how the Catholic Church views Peter's faith as the rock (even while, of course, believing that Peter himself is the rock).

"Moved by the grace of the Holy Spirit and drawn by the Father, we believe in Jesus and confess: 'You are the Christ, the Son of the living God. On the rock of this faith confessed by St. Peter, Christ built his Church." (CCC 424)

"Such is not the case for Simon Peter when he confesses Jesus as "the Christ, the Son of the living God", for Jesus responds solemnly: "Flesh and blood has not revealed this to you, but my Father who is in heaven." Similarly Paul will write, regarding his conversion on the road to Damascus, "When he who had set me apart before I was born, and had called me through his grace, was pleased to reveal his Son to me, in order that I might preach him among the Gentiles..." "And in the synagogues immediately [Paul] proclaimed Jesus, saying, 'He is the Son of God.'" From the beginning this acknowledgment of Christ's divine sonship will be the center of the apostolic faith, first professed by Peter as the Church's foundation." (CCC 442)

"Simon Peter holds the first place in the college of the Twelve; Jesus entrusted a unique mission to him. Through a revelation from the Father, Peter had confessed: "You are the Christ, the Son of the living God." Our Lord then declared to him: "You are Peter, and on this rock I will build my Church, and the gates of Hades will not prevail against it." Christ, the "living Stone", thus assures his Church, built on Peter, of victory over the powers of death. Because of the faith he confessed Peter will remain the unshakable rock of the Church. His mission will be to keep this faith from every lapse and to strengthen his brothers in it." (CCC 552)

In contrast, Protestants tend to see the rock only as the content and/or act of faith in Peter's confession. They tend not to see the significance (with respect to office) in Christ changing Simon's name to Peter and giving him the keys of the kingdom. They tend to read Matthew 18:18 as nullifying any uniqueness in Peter's office shown by Christ giving him the keys.

I have distinguished previously (here and here) between "comparing form" vs. "tracing matter". Here I'm pointing out that the Catholic Church believes that the Petrine office has preserved the faith of the Apostles, and that this is part of the significance of Matthew 16 -- Peter's being made a rock by Christ and being given the keys of the kingdom, and later being charged with feeding Christ's sheep and strengthening the faith of his brothers (the other Apostles) in John 21 and Luke 22. The Church believes that this matter (this office) has been given the keys, so as to preserve the form (i.e. the deposit of faith in its propositional and dynamic aspects) that was entrusted to it. The Church believes that the form and matter always remain united, just as the visible and invisible are held together in Christ's hypostatic union.