I have been discussing Matthew 16:18 for years now with both Catholics and non-Catholics. This verse is obviously a very important verse concerning the doctrine of the Bishop of Rome being Supreme Pontiff.
The non-Catholic argument that I come up against time and time again is the "play on words" interpretation summed up pretty well here.
I understand that, according to this interpretation, Jesus calls himself "big rock," and calls Peter "small rock."
Looking up the original Greek I see that Jesus is referring to two types of rocks and one is related to the other, but they are not the same.
Peter = Πέτρος, Pétros (a masculine noun) – properly, a stone (pebble), such as a small rock found along a pathway.
Rock = pétra (a feminine noun) – "a mass of connected rock”
The accepted answer goes on to say...
This revelation, being from God, is infallible, and if the Church is built upon it, it can never fall. Simon was named petros because he was the archetype, the first (of his contemporaries at least) to have received this personal revelation from God.
I've also heard other interpretations that place the "Rock-ness," if you will, on Peter's faith.
The answer above labels Peter as an "archetype" for those individuals with faith, or those individuals who receive infallible revelations.
I think this reads to much into it when considering the context of scripture, and is perhaps a presupposition.
Obviously Catholics believe that Christ, by changing Simon's name to Peter, established a foundational office of headship upon which the "Keys to the Kingdom of God" rests until his return. Catholics believe that that change signified a newly established office, and is why Christ changed Simon the fisherman to Peter the fisher of men to begin with.
"The keys of the kingdom"
551 From the beginning of his public life Jesus chose certain men, twelve in number, to be with him and to participate in his mission.280 He gives the Twelve a share in his authority and 'sent them out to preach the kingdom of God and to heal."They remain associated for ever with Christ's kingdom, for through them he directs the Church:
As my Father appointed a kingdom for me, so do I appoint for you that you may eat and drink at my table in my kingdom, and sit on thrones judging the twelve tribes of Israel.
552 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.
553 Jesus entrusted a specific authority to Peter: "I will give you the keys of the kingdom of heaven, and whatever you bind on earth shall be bound in heaven, and whatever you loose on earth shall be loosed in heaven."The "power of the keys" designates authority to govern the house of God, which is the Church. Jesus, the Good Shepherd, confirmed this mandate after his Resurrection: "Feed my sheep."The power to "bind and loose" connotes the authority to absolve sins, to pronounce doctrinal judgements, and to make disciplinary decisions in the Church. Jesus entrusted this authority to the Church through the ministry of the apostles and in particular through the ministry of Peter, the only one to whom he specifically entrusted the keys of the kingdom. (CCC 551-553)
My question is, from a non-Catholic point of view, why did Jesus choose "Rock" as a name for Peter in the first place? Answering whether or not Peter is called big rock or little rock doesn't answer why Jesus called him a rock - of any size.
I'm wanting to know why exactly non-Catholics believe Christ changed Peter's name (rock...big or small), and what does it signify in comparison to what the Catholic Church teaches.