Pope Francis told the crowd of pilgrims at World Youth Day's Saturday night prayer vigil that the "field of faith" is found in their own hearts, which Christ wishes to till.

"This, dear young people, means that the real 'Campus Fidei,' the field of faith, is your own heart, it is your life," the Pope told the pilgrims gathered in Rio de Janeiro at the beginning of a vigil July 27. The prayer vigil was held on Copacabana beach rather than "Campus Fidei" in Guaratiba, which was rained out.

He stressed that the deepest meaning of "Campus Fidei" is not a geographical place, like the massive plain east of Rio that was closed to pilgrims after heavy rains. Rather, the field of faith is, most profoundly, the human heart.

"It is your life that Jesus wants to enter with his word, with his presence. Please, let Christ and his word enter your life, blossom and grow."

Pope Francis examined his namesake, St. Francis of Assisi, as a model of Christian life. The saint was called to rebuild Christ's house, and realized that his call was not merely "a question of repairing a stone building, but about doing his part for the life of the Church."

Just as St. Francis was called to "make the countenance of Christ shine ever more brightly" in the Church, so "today too," he told the young people, God is "calling each of you to follow him in his Church and to be missionaries."

Taking the intended site of his speech as an inspiration, the Pope used the image of a field in three ways: a place for sowing seeds; a training ground; and a construction site.

The human heart is the field where Christ sows the seed of God's word, Pope Francis taught, using the imagery of the parable of the sower in Matthew 13. "What kind of ground are we? What kind of terrain do we want to be?"

At times, he said, "we are like the path," not allowing the word of God to change our lives because we have "let ourselves be numbed by all the superficial voices competing for our attention" instead of resting in calmness and slowness with the Lord.

We can also fail to bear fruit by faltering in the face of difficulties when "we don't have the courage to swim against the tide;" or at times "negative feelings" choke God's word in us.

Pope Francis encouraged the pilgrims, saying that "today I am sure that the seed is falling on good soil, that you want to be good soil."

He contrasted "good soil" with a desire to be Christian "part-time," "superficially," or "for show."

"Do not be Christians of the facade, be Christians who are authentic!" he said. "Ask for the Lord to sow his seed in your heart."

"I am sure that you don't want to be duped by a false freedom, always at the beck and call of momentary fashions and fads," he added.

Pope Francis encouraged them to be "aiming high," resolving to maintain the lofty standards of truth, goodness, and beauty.

The Bishop of Rome's next image considered the field of faith as an athletic training ground, saying that being a disciple of Christ is much like joining a soccer team. Both require discipline and training.

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He referred to St. Paul's writing that "athletes deny themselves all sorts of things" in order to "win a crown of leaves that withers," and then added that "Jesus offers us something bigger than the World Cup," soccer's international tournament which is to be held next summer in Brazil.

Christ offers "the possibility of a fulfilled and fruitful life; he also offers us a future with him, an endless future, eternal life," Pope Francis preached.

"But he asks us to train, 'to get in shape,' so that we can face every situation in life undaunted, bearing witness to our faith."

Such spiritual exercises, the Pope said, include talking with him in prayer, "our daily conversation with God." Do we really seek time in conversation with God, he asked, calling prayer also a "dialogue" with God.

Other spiritual exercises Pope Francis mentioned were the sacraments and loving one another, "yearning to listen, to understand, to forgive, to be accepting and to help others, everybody, with no one excluded or ostracized."

Finally, Pope Francis spoke of a field as a construction site, saying God constructs the Church of "living stones," and that "we are never alone" as we journey "on the same path."

"Jesus is asking us to build up his Church, but not as a little chapel which holds only a small group of persons. He asks us to make his living Church so large that it can hold all of humanity, that it can be a home for everyone!"

Christ says "to me, to you, to each of us," Pope Francis reflected: "Go and make disciples of all nations."

"Tonight, let us answer him: Yes, I too want to be a living stone; together we want to build up the Church of Jesus!"

The desire, so characteristic of young people, to build up a more just, fraternal society, Pope Francis said, must begin with each person becoming more just and fraternal.

Dear friends, never forget that you are the field of faith! You are Christ's athletes! You are called to build a more beautiful Church and a better world."

Mary is the model for building a beautiful Church and better world, he assured the pilgrims as he concluded.

"All together, let us join Mary in saying to God: let it be done to me as you say. Amen!"