21st Sunday in Ordinary Time
And I say to you, you are Peter, and upon this rock I will build my church, and the gates of the netherworld shall not prevail against it.
We do not hesitate to assert the Christ Jesus is the true rock upon which the Catholic Church is built – how could there be any other? And yet, we likewise affirm that Peter is the rock upon which Christ has built his Church; for the Greek is clear: “Peter” is petros while “rock” is petra, and the Aramaic would be clearer yet as the one word used for both was cepha.
It is as though Jesus said, “You are Rock (Petros/Cepha) and upon this rock (petra/cepha) [which is you], I will build my Church.” Christ is the rock and Peter is the rock, Christ is the foundation and Peter is the foundation. A man’s faith is founded upon Christ, only if it is founded upon Peter’s confession. Christ is the rock of the Church, only if the Church is set upon the rock of Peter’s profession of faith.
Let us consider why it is enough for the Pope to be infallible (i.e. unable to err in teaching), even if he is not impeccable (i.e. unable to sin).
The protestant counter-appeal to St. Augustine
The classic protestant exposition of this passage appeals to two interpretations given by St. Augustine. While the Doctor of Grace had considered this passage “You are Peter [Petros], and upon this rock [petra]” as stating that Peter himself is the rock upon which Jesus founded his Church, in later years he gives a preference for a variant interpretation:
“In a passage in this book, I said about the Apostle Peter: ‘On him as on a rock the Church was built’...But I know that very frequently at a later time, I so explained what the Lord said: ‘Thou art Peter, and upon this rock I will build my Church,’ that it be understood as built upon Him whom Peter confessed saying: ‘Thou art the Christ, the Son of the living God,’ and so Peter, called after this rock, represented the person of the Church which is built upon this rock, and has received ‘the keys of the kingdom of heaven.’ For, ‘Thou art Peter’ and not ‘Thou art the rock’ was said to him. But ‘the rock was Christ,’ in confessing whom, as also the whole Church confesses, Simon was called Peter. But let the reader decide which of these two opinions is the more probable.” (Retractations 20.1)
This passage tends to make some modern Catholics rather skittish. St. Augustine presents Peter not as the rock upon which Christ built his Church, but rather as a representative for the whole Church; further the rock is Christ and the Church is then built upon the confession of faith in Christ.
However, we will see that this very interpretation is perhaps the greatest proof for the necessity of Papal infallibility!
Papal infallibility as foundation of unity
We should recall the meaning of the term “Papal infallibility.” We do not claim that the Pope is impeccable (unable to sin), but only that he is infallible (unable to err). Furthermore, we certainly do not claim that, merely because he cannot err in certain instances, the Holy Father therefore knows everything and will teach everything in the clearest manner possible. Indeed, even exercising the charism of infallibility, the Pope could well speak in an extremely confusing manner or only teach one small portion of a much larger doctrine.
The simple claim of Papal infallibility is that, when teaching in a solemn manner as Supreme Pastor of the universal Church doctrines related to faith and morals and proposing them as to be believed by all, the Pope cannot err or teach a falsehood.
This charism of infallibility is given the Pope to preserve unity in the Church. Consider the words of the Second Vatican Council:
This Sacred Council, following closely in the footsteps of the First Vatican Council, with that Council teaches and declares that Jesus Christ, the eternal Shepherd, established His holy Church, having sent forth the apostles as He Himself had been sent by the Father;(136) and He willed that their successors, namely the bishops, should be shepherds in His Church even to the consummation of the world. And in order that the episcopate itself might be one and undivided, He placed Blessed Peter over the other apostles, and instituted in him a permanent and visible source and foundation of unity of faith and communion. (Lumen Gentium 18)
Now, the unity of the Church is founded upon the rock of Peter’s confession of faith – even as St. Augustine insists. Therefore, so that the Church may have her foundation upon solid rock, it is necessary that the solemn confession of both Peter and his successors (the Popes) should be preserved from every error, else the faith of the Church would be shaken.
If we say – as even the Protestants willingly admit – that the “rock” upon which the Church is established is the profession of faith by Peter, then we must be certain that the teaching office of Peter is as steady as a rock, both unchanging and free from error. This is precisely what infallibility guarantees!
Why the Pope doesn’t have to be without sin
Papal infallibility is given to preserve unity in the Church, but papal impeccability would have had no such benefit. It is necessary for Peter to be infallible, but he doesn’t have to be impeccable.
The confession of one (Peter) is able to be communicated to many (the Church) by the unity of common faith. It is for this reason that the Pope must be infallible (under the specific conditions), since the faithful are then united as one under the common faith professed by the Roman Pontiff.
However, the holiness of one is unable to be communicated to many, since the grace of one is sufficient only to the salvation of that man and no other. In other words, if the Pope is holy, I do not thereby become holy – if the Pope is a sinner, I do not thereby become a sinner.
While it is certainly beneficial to all that the Pope should lead by a good example of holiness, his own personal sanctity has no direct correlation to the holiness of the Church (even as many of the greatest saints were sent by God under the reign of some rather questionable Popes). On the other hand, if the Pope were to solemnly teach a falsehood, my faith would be shaken – since Christ established his Church upon the solemn confession of Peter and his successors.
This is why Peter’s confession benefits the whole Church, but Peter’s denial harms only himself. And Peter might well deny the Christ, but God would preserve him from ever solemnly teaching that Jesus was not the Christ.