By Carl Anderson

NEW HAVEN, Connecticut, AUG. 17, 2009 ( A few days ago, I came face to face with the future of the Catholic Church in the United States.

As more than 20,000 people packed Arena in Glendale, Arizona, to pay tribute to Our Lady of Guadalupe on Aug. 8, I saw gathered both the Church of tomorrow, and the unity Our Lady of Guadalupe brings to the Church and to the American hemisphere.

The event was co-sponsored by the Knights of Columbus, the Diocese of Phoenix, the Archdiocese of Mexico and the Instituto Superior de Estudios Guadalupanos. And in keeping with its international sponsors, the event drew a diverse crowd -- much of it Hispanic.

As I told those assembled there, the future of the Church will, in large part, depend on the influence of Hispanic immigrants, and this in turn will be influenced by the welcome these immigrants receive from those Catholics already in the United States.

These immigrants are not an abstraction. They are our fellow parishioners, and promise to be so in even greater numbers going forward.

We might think of Hispanics in the Church in terms of mythical phoenix: the bird that rose up again every 500 years. Nearly 500 years after Our Lady of Guadalupe's transformation of this hemisphere, our Hispanic brothers and sisters represent the possibility of a rebirth and revitalization of Catholicism in the United States.

According the U.S. bishops' conference, since 1960, 71% of the growth of the Catholic Church in the United States has been Hispanic. Hispanics now make up more than 35% of all Catholics in the United States -- and that number is growing.

Today, five centuries after Our Lady of Guadalupe appeared to Juan Diego and brought a new spiritual life into the ruins of a devastated empire, Hispanics have taken her image and her message and have breathed renewed life into the Church of the United States.

But we -- the Catholics of the United States -- have a great responsibility to assist in this process. We cannot be spectators, we must be active participants.

How Catholics welcome immigrants will largely set the tone of our common future as both a Church and a nation. Without our help and support, can we expect the Hispanic immigrants of today to become the Catholic parents of tomorrow?

With Hispanics making up more than half of all Catholics under age 25, it's a question we as Catholics cannot ignore.

The Catholic Church in the United States has great potential to be a model of cross-border unity, based upon a foundation of shared faith. It will require priest and laity to work together to find ways of reaching out to, and integrating, Hispanic Catholics.

One out of five Catholics in the United States is a Hispanic immigrant, so this is not a reality that can be ignored. We cannot delay in taking up this mission.

As citizens of a hemisphere that is indeed "a continent of baptized Christians," we must remember that just as Our Lady of Guadalupe points us to her son, she also points us to unity in her son, and for Catholics this unity of faith must transcend borders.

Benedict XVI said in his first encyclical "Deus Caritas Est": "To say that we love God becomes a lie if we are closed to our neighbor or hate him."

As Catholics, that means we must love every person: the immigrant, the unborn, the intellectually disabled.

We are not called to do anything that our mother -- Our Lady of Guadalupe -- has not done herself. She appeared to Juan Diego -- a humble Indian. She appeared as a mestiza -- a union of European and Native American cultures.

Following her example, we must embrace our immigrant Catholic brothers and sisters, realizing that they have an inherent dignity as a person, and that throughout the Americas all of us share a transcendent bond: a bond of faith.

In the United States, our churches are flourishing, revitalized by the presence of Hispanic Catholics who have lived so long with the Virgin in their homes. Like the many generations of European immigrants before them, they have brought a deep and refreshing faith to the United States.

Whether that faith fades or flourishes will depend on the reaction of those of us Catholics already in the United States, who are children of previous generations of Catholic immigrants.

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Carl Anderson is the supreme knight of the Knights of Columbus and a New York Times bestselling author.