VATICAN CITY (CNA/EWTN News) - On Sunday Pope Francis reflected on the May 13 canonization of the child visionaries St. Francisco and Jacinta Marto, saying that their faithfulness, despite their young age, reminds us to pay special attention to children in the ministry of the Church.

"In Fatima the Virgin chose the innocent heart and the simplicity of little Francisco, Jacinta and Lucia, as guardians of her message. These children received it worthily, so to be recognized as reliable witnesses to the apparitions, and to become models of Christian life."

"With the canonization of Francisco and Jacinta, I wanted to propose to the whole Church their example of adherence to Christ and of evangelical witness, and I also wanted to propose to the whole Church to take care of children," he said May 14.

The holiness of these children is not a consequence of the apparitions they received, he said, but of the "fidelity and ardor with which they returned the privilege they received of being able to see the Virgin Mary." 

"After the encounter with the 'beautiful lady,' as they called her, they frequently recited the Rosary, they did penance and offered sacrifices for the end of the war and for the most needy souls of divine mercy."

This is what made them saints, he said.

Pope Francis addressed around 25,000 people in St. Peter's Square Sunday afternoon before praying the Regina Coeli.

In his greeting, he expressed his gratefulness to God for the opportunity to make a pilgrimage to Fatima May 12-13 for the centenary of the apparitions, going "to the feet of the Virgin Mother as a pilgrim of hope and peace."

He also thanked the bishops of Portugal, and in particular the Bishop of Leiria-Fátima, António Augusto dos Santos Marto, as well as the local authorities and everyone who helped to organize the visit.

"Last night I returned from the pilgrimage to Fatima," he said, pausing to add a greeting to "the Madonna of Fatima!" followed by cheers from those present.

"In Fatima, I was immersed in the prayer of the holy faithful people, a prayer that flows there for a hundred years as a river, to beg Mary's maternal protection on the whole world," he went on.

"From the very beginning, when in the Chapel of the Apparitions I stayed for a long time in silence, accompanied by the prayerful silence of all the pilgrims, a together and contemplative climate was created where the various moments of prayer took place." 

And at the center of all of this, he said, was the Risen Lord present in the Eucharist.

Even 100 years after the first appearance of Our Lady of Fatima there is still a great need for prayer and penance for the grace of conversion, Francis said. We also need prayers "to implore the end of so many wars that are everywhere in the world... and which disfigure the face of humanity."

"Let us be guided by the light coming from Fatima. The Immaculate Heart of Mary is always our shelter, our consolation, and the way that leads us to Christ," he said.

Following the prayer, the Pope spoke with sympathy for the people affected by wars and conflicts in the Middle East, both Christians and Muslims, who suffer from violence and discrimination.

"My solidarity accompanies the memory of prayer," he said, thanking all those who provide humanitarian aid and encouraging "the various communities to follow the path of dialogue and reconciliation to build a future of respect, security and peace."

He also mentioned the beatification in Dublin May 13 of Jesuit priest John Sullivan, who lived during the 19th and 20th centuries in Ireland. He was devoted to the teaching and training of young people, the Pope said, "and was loved and respected as a father to the poor and the suffering."

Pope Francis concluded his address by mentioning the celebration of Mother's Day in several countries. "Let us remember with gratitude and affection all moms, even our moms in heaven, trusting them to Mary, the mother of Jesus," he said, concluding with a moment of silent prayer for mothers.