The passage
      v13. Jesus has moved away from the crowds to minister to (teach) his disciples. Caesarea Philippi, at the base of Mount Hermon and some 50 kilometers North of Galilee, is a Gentile town, and Jesus has moved into territory near this city.
      v14. Neither the crowds, nor the religious authorities, had come to recognize Jesus as the messiah. Herod Antipas, 14:2, thought he was John the Baptist risen from the dead. Many saw him as an Elijah figure, the promised prophet who precedes the messiah (the one crying in the wilderness). Others saw him as a Jeremiah figure, a prophet of doom, while others saw him as a prophet in general terms. In answering Jesus' question, the disciples mention only the positive opinions.
      v15-16. Jesus pushes the disciples to articulate their own understanding. Peter's confession probably expresses the opinion of all the disciples, namely, that Jesus is the messiah, "the Christ", sent by God to save Israel. The term, "Son of God", is a messianic title meaning "the Anointed One," and is not referring to Christ's relationship with the Father. God is "the living God" in that he is the source and giver of life.
      v17. Peter's knowledge that Jesus is the Christ is not human in origin. It is part of God's (general?) revelation to humanity. Now that Peter has observed it, he proclaims it.
      v18. Jesus plays with Peter's name, which means rock, and declares that on this rock he will build his church. The "rock" is most likely the priority of Peter and his confession of faith. He is the first of many believers who will stand up for Jesus and so become members of an eternal community.
      v19. Peter, as the first (in time) among many who will confess Jesus as "Son of the living God", is now described as the one who holds the keys of the kingdom. He, along with all those who follow in his footsteps, has the power to open the gates of the kingdom, or to close them, ie. give permission for people to enter the kingdom, or exclude people from it. This is done through the proclamation of the gospel and the entry, or exclusion, that follows either belief, or rejection.
      v20. Jesus reminds his disciples to keep the "messianic secret." Jesus didn't try to conceal his messianic identity, but rather reveal it in such a way as to draw out the true seeker, while at the same time confuse those opposed to the dawning kingdom. An overt disclosure would draw out many who were looking for a political leader to throw out the Romans.

The catholic church
      There is a sense where every Christian is a member of the "catholic" church. For example, the English Prayer Book uses the term "catholic" in a particular Biblical sense meaning "universal" - "the whole Catholick Church of Christ". Catholic then means all believers everywhere of whatever denomination - Christ's church universal; all believers past, present and future.
      In the New Testament, the word "church" means assembly, Christian or otherwise. Today the term is used exclusively of a Christian assembly. You can't have a Hindu church, although you can have a Hindu assembly. Although we are members of the one church, it has two forms. There is the local assembly we gather with regularly - daily, weekly, monthly.... whatever. There is no requirement on how often we meet, just that we "don't forsake the gathering together of the brotherhood". As we meet, Jesus is present with us. This is his promise. The other form of the church is the heavenly gathering with Christ. Although we await the resurrection of the dead, there is a sense where even now we are "raised up with Christ and seated with him in the heavenly realms", Eph.2:6. At the day of resurrection we will all gather at the same moment, to be with Christ for eternity. That reality is so real that the apostle can speak of it as a present reality. This then is the catholic church, the universal Christian church. When we gather with our brothers and sisters in the Lord, we mimic the eternal gathering of all God's people. As we gather we are part of an eternal whole.
      The church that Jesus tells Peter he is about to build, is the universal eternal community of believers. Jesus' words to Peter tell us something of this church.
        i] Membership is gained by confessing Christ. Christ's eternal community is made up of those who trust him for their eternal security. There are no other entrance requirements. When we trust Jesus, "the Son of the living God", we are eternally secure in him.
        ii] Christ's community is eternal. It is not a religious fad which will fade out with the passing of time. Nor can spiritual powers of evil overcome Christ's eternal community.
        iii] Christ's community is functional. Each individual member of Christ's fellowship has both the authority and responsibility to offer God's forgiveness and total acceptance to all who seek his mercy in Christ.
      When we have a big-picture view of the church we need no longer feel alone, vulnerable or afraid.

v14
      oiJ men .. .. alloi ... eJteroi "some [say] ... others .... still others" - some ... others .... others. A unique construction for the NT.

v15
      uJmeiV de "but what about you?" - [he says to them], but you. The conjunction is adversative and the personal pronoun, "you", is emphatic. "But you, he said", NJB.

v16
      oJ CristoV "the Christ" - With the article the meaning is messiah, the anointed one, the coming one, as promised in the Old Testament.
      oJ uiJoV tou qeou "Son of [the living] God" - son of God. Here simply the messianic title, the Anointed One.
      tou zwntoV (zaw) part. gen. "living" - of the living one. The term is not indicating that God is alive rather than dead, but descriptive of God as the source of all life and the giver of life. Mostly translated as an attribute of God, "the living God", but it can serve to separate God from the other dead gods, no gods; "the Son of God, the living one (as distinct from those gods who aren't)."

v17
      makarioV adj. "blessed" - Possibly "happy", "fortunate", but more in the terms of spiritual blessing, "favoured", REB
      Bariwna "son of Jonah" - bar-Jona. This is the only reference to Peter's full name. Possibly a shortened version of Johanan = John, Jn.1:42. Possibly also, "someone like Jonah."
      sarx kai aiJma "by man" - flesh and blood. The disciples did not come to this understanding by means of the instruction of a "mortal man." Peter's understanding is still limited. He had not yet grasped the significance of a suffering messiah. It is therefore, difficult to understand the full weight of Jesus' words "my Father in heaven" "revealed to you". In what sense was Peter's present understanding of Jesus divinely revealed? It may be a specific revelation, but more likely part of the general revelation of God to humanity. Any knowledge of the Divine is totally dependent upon His self revelation.

v18
      su ei PetroV "you are Peter" - Possibly giving Peter a special name, but more likely identifying Peter as the person who has just made this significant statement of faith.
      petra/ (a) fem. dat. "rock" - usually referring to a large stone, even a large hewn stone. Certainly, not a rock that can be thrown. The meaning of this image is unclear. Is the "rock" Jesus, Peter, the confession of faith, or the content of the confession? Protestants have rejected the idea that Peter is the rock, rejecting also the Roman Catholic teaching that Peter's successors (the Popes) possess infallibility on matters of religion and authority over the church. Protestants have tended to see the rock as either Christ, or more particularly, Peter's confession of faith. The trouble is, the text does say that the rock is Peter. Elsewhere Jesus is the rock, but here Peter is the rock and Jesus is the builder. The context always determines meaning. Jesus is probably saying that Peter is the first among equals (not by any means perfect or superior to the other apostles) and upon his confession of faith, Jesus will build his church. That is, Christ's last-days community ("church", literally "assembly") will be built (gathered-in and prepared for reign in eternity) as others join with Peter in the acceptance of Jesus as messiah (the anointed one sent by God to establish his eternal kingdom).
      thn ekklhsian (h) "church" - assembly, community, group. Gathered assembly, not organization.
      pulai (h) "gates" - In the Old Testament the phrase "the gates of Hades" refers to death, Job.17:16, Isa.38:10 etc. When related to the assembled community of believers, built by Jesus the messiah, it probably means that the church will not fade away in the passing of time, as have other religions. Jesus may also be saying that the church will stand against the powers of darkness. Satan and his crew ("gates" - the fortress of evil) may attack the rock-fortress of the church, but will not succeed in their assault.
      aJdou (hV ou) "hades" - the underworld. A conservative translation of the word would be "death". Thus "death" will not overcome the church - it won't die out. Still, Matthew may have in mind the powers of darkness, Satanic powers.
      katiscusousin (katiscuw) fut. "overcome" - to overpower, have mastery over; "and death itself will not have any power over it", CEV.

v19
      taV kleidaV (eiV eidoV) "keys" - Probably the gospel, see below.
      oJ ean "whatever" - whoever. Jesus is referring to people not things, as in NIV. "Whoever you bind."
      dhsh/V (dew) aor. subj. "you bind" - you may have bound. A Jewish technical term meaning "forbid" (loose = permit) = hindered or restricted from entering the kingdom of heaven, excluded from membership. Jesus says that the teachers of the law "hindered" those who were seeking to enter the kingdom because of their false teaching, ie. they took away "the key of knowledge", Lk.11:52. Peter, possessing the gospel revealed to him by the "Father in heaven", can now proclaim a message with the power to free people to enter the kingdom of heaven, or bind for judgement those who reject it. The gospel is the key that unlocks the bounty of God's heavenly blessing already made available in the person and work of Jesus. As to those who have the right to use the key, all who confess Christ, as Peter confessed Christ, have the right to use the key.
      estai dedemonon "will be bound" - shall have been bound. Whoever Peter, and those who stand with Peter, binds, "shall have been bound", and whoever he looses, "shall have been loosed". The tense used in these phrases (periphrastic future perfect) is very important in the translation of this verse because "the church on earth carries out heaven's (God's) decisions, not heaven (God) ratifying the church's decisions", Albright and Mann. See Chamberlain for the grammar. The NIV translation implies that our binding and loosing is ratified by God, whereas we are acting on the basis of a previous divine action. Through the power of the key, Peter, and consequently, all believers, can "bind" or "loose".