My theory has always been that Jesus "pulled" Peter "aside" and told him these things because Peter was the weakest of the disciples. The rock is NOT Peter, the rock and foundation of the Church is Jesus. Peter was the one who denied Christ THREE times. I think Jesus was giving him a friendly reminder of what their job was to be in the coming times. There's no indication that Jesus was raising Peter over and above the other disciples. Unless, of course, you base your views on tradition rather than scripture.
Jesus calls Peter "blessed" (
makarios in Greek). This word always denotes the blessedness of the person whose relationship to God is correct and holy. Read Mt. 5:1-11; Rom. 4:7-8; Lk. 1:45. There is another word for "blessed" (
eulogetos in Greek) which is used only of God and means "Praise". For example, Lk. 1:68
Okay. What "role" did Christ give "individually" to Peter? Well, in Matthew 16:17-19, Christ individually imparts to Peter the office of "Rock," "Key-bearer," and the authority to "bind and loosen." Also, in Luke 22:31-32, the Lord individually imparts to Peter the task of strengthening his brethren (i.e. the other Apostles). Also, in John 21:15-19, the Lord makes Peter a shepherd, telling him three times to "feed my lambs" and "tend my sheep."
Here's a simple question: Are any of these things exclusive to the full measure of Peter's Apostolic office? Answer: No, they are not. And why? Because, Peter, like the other eleven, were made Apostles
WAY BACK in Matthew 10:1-8, which was
LONG before Peter was
individually granted any of these other duties or responsibilities. And, speaking of Matthew 10 here, verses 7-8 tell us what the office of an Apostle is: It is a Christ-appointed office to proclaim the Gospel -- to deliver the fullness of
new revelation to mankind. In this sense, and according to this Apostolic ministry, Peter was merely one of the Twelve and, as one of the Twelve, his Apostolic office was directed primarily toward to the Jews (Gal 2:7-9). Yet, as is clear from Scripture, the
EPISCOPAL DIMENSION of Peter's Apostolic office carried other, additional responsibilities, which were given to him
individually by Christ. And these responsibilities concerned maintaining the
entire flock (the universal Church) in unity and orthodoxy. And this is exactly what we see Peter doing throughout the New Testament.
What's more, and I began to touch on this above, the authority to "bind and loosen" given to Peter in Matt 16:19, and to the Apostles collectively in Matt 18:18, is not an aspect of their primary Apostolic ministries, but rather an
episcopal charism, involving the
episcopal dimension of their offices, and one that is passed down to their
episcopal successors. If anyone doubts this, he need only look at Matt 18:18 in context (i.e. Matt 18:15-18), and see that this authority to "bind and loosen" involves church government, viz. excommunication and the like -- an authority that is certainly still possessed by the Church today, even without the presence of true Apostles.