On the Sunday before the conclave begins, a good many cardinals will visit their “titular churches” in Rome. This Sunday they will have a Gospel text that should inspire their preaching as they ready themselves to elect a new pope.

The assigned reading for this Sunday is John 21:1-19. Jesus asks Peter three times to profess his love, and three times confers upon him the mission of caring for the entire flock — “feed my lambs, tend my sheep.” As it is the assigned reading for Sunday Mass all over the world, homilists everywhere will likely preach about Peter’s primacy.

Every cardinal, upon receiving the red hat, is assigned a church in Rome, becoming, as it were, the local parish priest. He is not actually that, but the titular assignment maintains an ancient tradition that a bishop is selected by the local clergy — in this case, that the bishop of Rome is elected by the clergy of Rome. The College of Cardinals expresses the universality of the entire Church; their titular churches link them to the local diocese of Rome.

The pre-conclave visits for Sunday Mass can create quite a commotion. The cardinals who live far away from Rome rarely visit their titular churches, so any visit can be something of a local event.

Given the fevered atmosphere just before a conclave, the most prominent cardinals attract an inflated congregation of supporters, curiosity-seekers and media. What did the apparent front-runners say? Did it help or hurt their cause? What preferences did the so-called kingmakers express? Were there intercessory prayers in Mandarin? Were there prayers for persecuted Catholics? It can be a bit of a spectacle.

John 21 is also used at papal funerals. It was used for both Pope Francis and Pope St. John Paul II. Cardinal Giovanni Battista Re, who preached last week, barely took notice of the Gospel passage in his formulaic homily rehearsing the life of Pope Francis. The cardinals will certainly do better than that this Sunday.

In 2005, Cardinal Joseph Ratzinger delivered a homiletic masterpiece at John Paul’s funeral, built around the final words of Jesus to Peter: Follow me! One hopes the cardinalatial preachers can approach Cardinal Ratzinger’s heights this Sunday.

The greatest of all pre-conclave homilies was preached on that very text, John 21, in October 1978. Blessed John Paul I had died after only 33 days, and the stunned cardinals gathered for the second conclave that year.

After arriving in Rome, the Polish cardinals offered a Holy Mass for the late pope. Cardinal Stefan Wyszyński, primate of Poland, was the principal celebrant, and Cardinal Karol Wojtyła, archbishop of Kraków, preached the homily on the conversation between Jesus and Peter.

There is no video of the occasion and it was largely unknown until papal biographer George Weigel included it in Witness to Hope, the 1999 biography of John Paul II. Weigel discovered it in the Kalendarium życia Karola Wojtyła, an exhaustive pre-papal chronology compiled by Adam Boniecki.

With near-mystical quality, the future pope preached that day about his immediate predecessor, John Paul I, and his first predecessor, St. Peter:

The succession of Peter, the summons to the office of the papacy, always contains within it a call to the highest love, to a very special love. And always, when Christ says to a man, ‘Come, follow me,’ He asks him what He asked of Simon: ‘Do you love me more than these?’”

The question at the heart of every vocation is the same: “Do you love me?” But the Petrine office, to be the Vicar of Christ, is so terrifying, that the heart cannot bear the weight. Cardinal Wojtyła again:

Then the heart of man must tremble. The heart of Simon trembled, and the heart of Albino Luciani, before he took the name John Paul I, trembled. A human heart must tremble, because in the question there is also a demand. You must love! You must love more than the others do, if the entire flock of sheep is to be entrusted to you, if the charge, ‘Feed my lambs, feed my sheep’ is to reach the scope which it reaches in the calling and mission of Peter.

It is a truly remarkable passage. On the threshold of the papacy in 1978, Cardinal Wojtyła already felt the weight of the call — a weight too heavy for the heart of man. The Polish cardinal’s heart no doubt trembled. In order for the Church to receive the gift of Peter, one man must be willing to pay the price. Peter paid that price with his life, crucified upon the Vatican hill.

Cardinal Wojtyła’s homily again:

Christ speaks enigmatic words, He says them to Peter: ‘When you were younger, you girded yourself and went where you wanted. But when you grow old, someone else will gird you and lead you where you do not want to go.’ Mysterious and enigmatic words. … And so in this summons, directed to Peter by Christ after His Resurrection, Christ’s command, ‘Come follow me,’ has a double meaning. It is a summons to service, and a summons to die …

Just days later, that summons would fall upon Cardinal Karol Wojtyła of Kraków. As all popes are, he was asked in the conclave: “Do you accept your election?” He was really being asked, in the Sistine Chapel, before Michelangelo’s immense Christ the Judge: “Do you love me more that these?”

Twenty-five years later, in October 2003, at the silver jubilee of the pontificate, John Paul II returned to John 21:

Every day the dialogue between Jesus and Peter takes place in my heart. In spirit, I fix my gaze on the Risen Christ. He, well aware of my human fragility, encourages me to respond with trust as Peter did: “Lord, you know everything; you know that I love you” (John 21:17). And then He invites me to assume the responsibilities which He himself has entrusted to me.

In his long pontificate, when John Paul spoke of his papal office, he preferred the text of Luke 22:32. Jesus, predicting Peter’s denial, assures him that he has prayed for him that his “faith may not fail” and that Peter will return and have the mission of strengthening the others in their faith. Less frequently did John Paul take up the more well-known Petrine passages in Matthew 16 and John 21. But in John Paul’s internal life of prayer with the Lord, it was the conversation of John 21 that accompanied him always.

At John Paul’s great funeral Mass in 2005, Cardinal Ratzinger placed the entire pontificate with the context of John 21:

In the first years of his pontificate, still young and full of energy, the Holy Father [John Paul II] went to the very ends of the earth, guided by Christ. But afterwards, he increasingly entered into the communion of Christ’s sufferings; increasingly he understood the truth of the words: ‘Someone else will fasten a belt around you.’ And in this very communion with the suffering Lord, tirelessly and with renewed intensity, he proclaimed the Gospel, the mystery of that love which goes to the end (cf. John 13:1).

In conferring the primacy upon Peter, Jesus placed it within the mystery of love. A love so deep and broad that the heart of man can hardly contain it. Thus the heart trembles.

On Sunday, for many of the cardinals, the homily will be their final public words before the conclave begins on Wednesday. Then, for one man, the summons will approach, and the heart will tremble.