KRAKOW, Poland — It’s hard to describe the feeling of not wanting to leave a sports arena on a Sunday night. I sat on the edge of the stage of the Tauron Arena in downtown Krakow at 7 p.m. a week ago now, looking around and remembering.

Beautiful things happened there during the days known as World Youth Day, before and during Pope Francis’ visit to Poland. The fruit of love, labor, vision and prayer was an at-capacity arena, day after day after day, filled with 20,000 young people deepening their faith.

The arena, a recent addition to Krakow and the largest venue it has, was home all week to English-speaking World Youth Day pilgrims — many, if not most, Americans. The Knights of Columbus were host to three days of catechesis from Boston’s Cardinal Sean P. O’Malley, Cardinal Luis Tagle of the Philippines, and New York’s Cardinal Timothy Dolan.

But the cardinals were not the stars of the show. The focus was on Jesus Christ, and the love these young people have for Him.

The themes of the Mercy Centre were freedom, solidarity, the cross, and vocation. The effect was to create formational moments that could be the renewal of civilization in not-so-small ways, moments that could just lead to the kind of human flourishing our culture and miserable politics and broken painful lives — often inundated with burdens and lies, heartaches, and loneliness – seem to cry out for.

At times on Saturday night at Camp Misericordia, the open-air field where a youth vigil with the pope was held, it seemed Francis was speaking directly to the young people of the United States, in an especially pointed and tender way, with all his fatherly heart.

He told them that the world is not content with them being couch potatoes. You know of what he speaks: the distractions, the isolation–even as we are more interconnected then ever. There’s a restlessness that becomes a desperation when the roads the world points to prove so achingly insufficient. This is not how we are meant to live. This is not freedom.

I didn’t want to pull myself away, because there was freedom here. These young people gathered in a country where such displays — from Holy Mass and Eucharistic adoration to papal visits — not all that long ago were not only unthinkable, but illegal.

World Youth Day’s patron saint, St. John Paul II, was so present at this one, the 31st. The witness of his holy life of moral leadership proves anything is possible with God, and nothing less than faithfulness is the Christian call.

There’s no doubt that vocations were hatched and nourished in Krakow this summer — to the priesthood, to religious life, and matches that will become marriages were made. (The World Youth Day record over the years testifies to this, and there was something in the air that gives one confidence about the future.) Young pilgrims in Krakow were set on a course to become ever more attuned and attentive to whatever it is the loving Father wills.

On his last stop in Krakow, Pope Francis stayed with a theme that ran throughout his visit to Poland for World Youth Day: Memory.

Referring to the next World Youth Day, in Panama, he said to the volunteers gathered at the arena:

“I don’t know if I’m going to be in Panama, but I can tell you one thing: Peter will be in Panama. And Peter is going to ask you if you talked with your grandparents if you talked with the elderly in order to remember, and if you had the courage and bravery to meet situations head on and in that way to sow seeds for the future. And you are going to have to answer to Peter. Right?”

As Tauron Arena returned to the games and concerts for which it was made, the people who were there during its Mercy Centre days will never be the same. You can’t meet the Lord and be unchanged. You can’t truly encounter Him in brothers and sisters in the Church– His very Body – and go on living as you were.

When I finally left Tauron one last time, I did so with confidence that the Spirit which permeated this place cannot truly depart, and that perhaps without realizing what they are walking into, people will be touched by a peaceful Presence that had 20,000 transfixed on Him and Him alone.

And those 20,000, changed by the time they spent with Christ, as the Body of Christ, can go on to be the missionary disciples their baptism commissioned them to be.

If my conversations and experience are any indication, young people and those who accompanied them left Krakow more convinced than ever of the final victory that was won for them by Jesus Christ on the Cross. Their commitment to Him, and His Gospel, is their mission.

As the theme for the Holy Father’s visit to the U.S. last fall put it, love is their mission, as they become ever more people of the Beatitudes. This knowledge of their identity as Christians and its urgent, inescapable responsibility in love is exactly what the world – their families, their communities, their countries — needs.