“This day has been made holy by the passion of the blessed apostles Peter and Paul. We are, therefore, not talking about some obscure martyrs. For their voice has gone forth to all the world, and to the ends of the earth their message. These martyrs realized what they taught: they pursued justice, they confessed the truth, they died for it.
Saint Peter, the first of the apostles and a fervent lover of Christ, merited to hear these words: I say to you that you are Peter, for he had said: You are the Christ, the Son of the living God. Then Christ said: And I say to you that you are Peter, and on this rock I will build my Church. On this rock I will build the faith that you now confess, and on your words: You are the Christ, the Son of the living God, I will build my Church. For you are Peter, and the name Peter comes from petra, the word for “rock,” and not vice versa. “Peter” comes, therefore, from petra, just as “Christian” comes from Christ.
As you are aware, Jesus chose His disciples before His passion and called them apostles; and among these almost everywhere Peter alone deserved to represent the entire Church. And because of that role which he alone had, he merited to hear the words: To you I shall give the keys of the kingdom of heaven. For it was not one man who received the keys, but the entire Church considered as one. Now insofar as he represented the unity and universality of the Church, Peter’s preeminence is clear from the words: To you I give, for what was given was given to all. For the fact that it was the Church that received the keys of the kingdom of God is clear from what the Lord says elsewhere to all the apostles: Receive the Holy Spirit, adding immediately, whose sins you forgive, they are forgiven, and whose sins you retain, they are retained.
Rightly then did the Lord after His resurrection entrust Peter with the feeding of His sheep. Yet he was not the only disciple to merit the feeding of the Lord’s sheep; but Christ in speaking only to one suggests the unity of all; and so he speaks to Peter, because Peter is first among the apostles. Therefore do not be disheartened, Peter; reply once, reply twice, reply a third time. The triple confession of your love is to regain what was lost three times by your fear. You must loose three times what you bound three times; untie by love that which your fear bound. Once, and again, and a third time did the Lord entrust His sheep to Peter.
Both apostles share the same feast day, for these two were one; and even though they suffered on different days, they were as one. Peter went first, and Paul followed. And so we celebrate this day made holy for us by the apostles’ blood. Let us embrace what they believed, their life, their labors, their sufferings, their preaching and their confession of faith.” -St Augustine, from the Office of Readings