If I wanted to convey some sense of the week in Philadelphia for the World Meeting of Families, I could write about isolated images of joyful individuals and whole families, nuns and priests, and even bishops, gathered as the body of Christ in the city.

When it was over, though, I had to wonder how the leader of a faith reviled by elite and popular culture had suddenly become a beloved figure of national affection and interest. America was “All Francis, All the Time.” It was wall-to-wall coverage. It was inescapable.

Was it merely the response to a cult of personality, a group madness stoked to frenzy by cheering crowds and then transmitted via media?

It’s a valid question, and it would be flatly dishonest to say group dynamics — the “madness of crowds” — had no role whatsoever. When crowds behave the way they did this week, a certain portion of the crowd is responding to collective emotions.

But that’s not what lay at the heart of it all.

Was it just a function of politics and its media enablers, with people using the Pope to advance elements of their own agendas? Sure, that was there, too.

The only way I can get at the core of this experience — my experience — is to try to find words to describe something that lies beyond words. I was part of a press contingent covering the Mass at the Cathedral-Basilica of Sts. Peter and Paul for priests and religious from an organ loft at the back of the side chapel.

It’s easy to tell when Francis is coming anywhere: The surge of cheers gets louder.

We hear the cheers. There’s a kind of strange silence; everything seems poised. The camera is pointed at the large doors of the basilica. He enters. Everyone in the chapel surges forward.

But they really don’t. No one moves from their pews. They stand to cheer, but stay in place. Yet the entire center of gravity in the room shifts to a single point of focus. A charge like electricity crackles through the room. It’s like flipping a switch.

The people settle down to participate in the most beautiful, perfectly executed liturgy I’ve ever experienced. When it is done, Francis leaves through the side and comes into our chapel, and it happens again: The switch is flipped, and the collective charge of emotion surged forward to focus on this one man as he stops to bless a sick boy, bless a weeping women, and smiles and laughs with us for a moment.

What was it?

It was an experience of pure emotion, beyond the complex theology and weighty issues. It shot straight to the heart.

It was joy and love, pouring out of our souls: joy and love that could only be poured out because it was already poured in by the Holy Spirit.

It had found a living, breathing focus: a man, yet not the man himself. Sure, Jorge Mario Bergoglio is an appealing figure for many: plain-spoken, loving, with a common touch and an appealing, essential message. But if Jorge Mario Bergoglio had finished Mass and walked in that chapel, the response would not have been the same.

The Seat elevates the man. The man who takes the Seat is a living connection to Peter, and thus to Christ. He is Christ’s vicar on earth. Christ left us many gifts, and one of them was Peter.

Not Simon. Simon died upside down on the cross. His bones are buried underneath the basilica that bears his name.

Jesus didn’t leave us Simon. He left us Peter, and each man in his turn who has taken that Seat reminds us of that unbroken gift.

Why did he leave us a man? A fair number of thoroughly rotten men have sat in that Seat over the course of two millennia. Did Jesus intend to leave us John XII or Alexander VII?

Of course not. We did that ourselves.

But he left the role, to be filled by a man, and for a very good reason.

Jesus walked the earth, the incarnate Word become flesh. He took flesh for many reasons that would take much complex theology to explain, but at least, in part, he took it in order to walk among us as one of us. Because we need that: the human face, the human voice, the human touch.

He left us Peter so we would have a reminder of that time, because we need that, too: not merely a leader or a teacher, but a man whose role bridges time and space, drawing the past forward into the present. The man may or may not be worthy of the role, but the role is a living symbol of unity and a connection to the very origin of the Church.

Our age is sick, our nation is broken, and the ground seems to be shifting beneath our feet.

Then along comes Francis, preaching the heart of the Gospel and recalling the very origins of a faith that changed the world and which is so desperately needed today. He comes to us insisting that we live out Luke 4:18:

“The Spirit of the Lord is upon me, because he has anointed me to proclaim good news to the poor. He has sent me to proclaim liberty to the captives and recovery of sight to the blind, to set at liberty those who are oppressed and declare a year of the Lord’s favor.”

And everywhere he went, I saw joy, love and something I haven’t seen on faces for a long time: hope.

Thomas McDonald covered the papal visit in

Philadelphia for the Register.