[Y]ou are Peter; and upon this rock I will build my church, and the gates of hell shall not prevail against it. And I will give to you the keys of the kingdom of heaven. And whatsoever you shall bind upon earth, it shall be bound also in heaven: and whatsoever you shall loose on earth, it shall be loosed also in heaven.
Mt. 16, 18-19
Today the Church celebrates the feast of the cathedra Petri, the Chair of St. Peter, and looks back at her creation, her establishment by Jesus Christ upon the rock that is St. Peter. The promise recounted in the Gospel of Matthew, which I quote above, continues to be a backbone of the Church’s identity. It shows that she is not a human construct, although she consists of humans – after all, Christ Himself established the Church. It conveys a unity upon the Church which literally no one or nothing outside her can disrupt. That is why any splits can never lead to two separate Churches. There is and always has been the one Church that Christ established for us Himself.
The papacy, the long line of successors to St. Peter as leader of the Church in Rome, also finds part of its origin in these verses (the other is Christ’s command to Peter to shepherd His flock). The rock that was St. Peter did not suddenly vanish when he died. It continues as the foundation of Christ’s Church on Earth, and we can see it every day in the person of the pope. As my priest said before Mass began today: the Holy Father is the sign of our unity.
In Caelo et in Terra 