Today, the Universal Church marks the Feast of the Chair of St. Peter. The Church invites us to reflect on the meaning of the authority of the Holy Father as the Successor of St. Peter.
Authority, in the eyes of the Church, is always tied to servanthood. We see this most profoundly expressed in the Evening Mass of the Lord's Supper. In St. John's Gospel account, Jesus, who is Lord and Master, takes on the posture of a slave:
He cometh therefore to Simon Peter. And Peter saith to him: Lord, dost thou wash my feet?  Jesus answered, and said to him: What I do thou knowest not now; but thou shalt know hereafter.  Peter saith to him: Thou shalt never wash my feet. Jesus answered him: If I wash thee not, thou shalt have no part with me.  Simon Peter saith to him: Lord, not only my feet, but also my hands and my head.  Jesus saith to him: He that is washed, needeth not but to wash his feet, but is clean wholly. And you are clean, but not all.
 For he knew who he was that would betray him; therefore he said: You are not all clean.  Then after he had washed their feet, and taken his garments, being set down again, he said to them: Know you what I have done to you?  You call me Master, and Lord; and you say well, for so I am.  If then I being your Lord and Master, have washed your feet; you also ought to wash one another's feet.  For I have given you an example, that as I have done to you, so you do also.One of the Holy Father's titles is "Servant of the Servants of God." While the Holy Father does not literally bend down and wash our feet, the Vicar of Christ spends himself in the service of the Church on a daily basis.
Part of this service involves his ministry as the Church's chief teacher. When he speaks officially, he does so ex cathedra, from the Chair. In this case, that Chair is housed at the Basilica of St. John Lateran. Perhaps the best explanation of this important aspect of the Petrine office comes from Pope Benedict XVI, himself, in the homily he preached the day he took possession of the Cathedra at the Lateran Basilica, the Pope's Cathedral:
The power and grace required for this service are conferred upon Bishops through the sacrament of Episcopal Ordination. In this network of witnesses, the Successor of Peter has a special task. It was Peter who, on the Apostles' behalf, made the first profession of faith: "You are the Messiah, the Son of the living God" (Mt 16: 16).
This is the task of all Peter's Successors: to be the guide in the profession of faith in Christ, Son of the living God. The Chair of Rome is above all the Seat of this belief. From high up on this Chair the Bishop of Rome is constantly bound to repeat: Dominus Iesus - "Jesus is Lord", as Paul wrote in his Letters to the Romans (10: 9) and to the Corin-thians (I Cor 12: 3). To the Corinthians he stressed: "Even though there are so-called gods in the heavens and on the earth... for us there is one God, the Father... and one Lord Jesus Christ, through whom everything was made and through whom we live" (I Cor 8: 5).
The Chair of Peter obliges all who hold it to say, as Peter said during a crisis time among the disciples when so many wanted to leave him: "Lord, to whom shall we go? You have the words of eternal life. We have come to believe; we are convinced that you are God's holy one" (Jn 6: 68 ff.).Interestingly enough, even though the Holy Father preached these words on the Solemnity of the Ascension, they incorporate some of today's antiphons and readings. In today's Entrance Antiphon, Jesus tells St. Peter that he is to strengthen his brothers in the Faith. In today's Gospel, the key scriptural reference to the Petrine ministry, Peter makes the profession of Faith declaring Jesus to be the Son of God. One could say that this was the very first Papal declaration. In the Communion Antiphon, Peter makes his declaration concerning Jesus, while Jesus makes his proclamation concerning Peter. He gives Peter His own authority to bind and loosen, adding that whatever decision the Prince of the Apostles makes will be ratified in heaven. Jesus has given St. Peter and his successors, the everlasting assurance of His protection and support.
The One who sits on the Chair of Peter must remember the Lord's words to Simon Peter at the Last Supper: "...You in turn must strengthen your brothers" (Lk 22: 32). The one who holds the office of the Petrine ministry must be aware that he is a frail and weak human being - just as his own powers are frail and weak - and is constantly in need of purification and conversion.
But he can also be aware that the power to strengthen his brethren in the faith and keep them united in the confession of the Crucified and Risen Christ comes from the Lord. In St Paul's First Letter to the Corinthians, we find the oldest account we have of the Resurrection. Paul faithfully received it from the witnesses. This account first speaks of Christ's death for our sins, of his burial and of his Resurrection which took place the third day, and then says: "[Christ] was seen by Cephas, then by the Twelve..." (I Cor 15: 4). Thus, the importance of the mandate conferred upon Peter to the end of time is summed up: being a witness of the Risen Christ.
The Bishop of Rome sits upon the Chair to bear witness to Christ. Thus, the Chair is the symbol of the potestas docendi, the power to teach that is an essential part of the mandate of binding and loosing which the Lord conferred on Peter, and after him, on the Twelve.
In the homily that the Holy Father preached the day after he ascended to to the Chair of St. Peter, Pope Benedict XVI expounded on that dialogue between Jesus and St. Peter:
I am thinking back at this moment to what happened in the neighbourhood of Caesarea Philippi some 2,000 years ago. I seem to hear Peter's words: "You are the Christ..., the Son of the living God", and the Lord's solemn affirmation: "You are "Peter' and on this rock I will build my Church.... I will entrust to you the keys of the kingdom of heaven" (cf. Mt 16: 15-19).Today, more than ever, the Successor of Peter needs our prayers and our support. He is being attacked from all sides. Jesus wanted Pope Benedict XVI to be the "rock" that supports us, that rock on which the Church Christ founded stands. Let us storm heaven, asking the Lord to bless and protect the Holy Father. Let us ask for St. Joseph's intercession, that he may assist his namesake with the task of safeguarding the Church. Let us implore the Blessed Virgin Mary to keep leading Pope Benedict to "do whatever" her Divine Son tells him to do.
You are Christ! You are Peter! I seem to be reliving the same Gospel scene; I, the Successor of Peter, repeat with trepidation the anxious words of the fisherman of Galilee and listen once again with deep emotion to the reassuring promise of the divine Master. Although the weight of responsibility laid on my own poor shoulders is enormous, there is no doubt that the divine power on which I can count is boundless: "You are "Peter', and on this rock I will build my Church" (Mt 16: 18). In choosing me as Bishop of Rome, the Lord wanted me to be his Vicar, he wanted me to be the "rock" on which we can all safely stand. I ask him to compensate for my limitations so that I may be a courageous and faithful Pastor of his flock, ever docile to the promptings of his Spirit.