The Pontiff said this today before departing to Rome from the Tarbes-Lourdes Pyrénées Airport, where he received an official farewell from Prime Minister François Fillon, at the end of his four-day trip to France.
The Holy Father described his visit to France as a "diptych," which is a painting or altarpiece that is composed of two panels, and attached by a hinge.
He said the first panel was his two-day visit to Paris. On Friday he met with political, cultural and religious leaders before meeting with the youth of France in front of Notre-Dame Cathedral, which he called "an all too brief, yet intense moment."
On Saturday, Benedict XVI celebrated Mass on the Esplanade des Invalides, which was attended by 260,000 people.
The Pope said there he "met a vibrant people, proud of their firm faith. I came to encourage them to persevere courageously in living out the teaching of Christ and his Church."
He also mentioned the vespers he prayed with priests, men and women religious, and seminarians, a moment in which, as he acknowledged, "I wanted to affirm them in their vocation in the service of God and neighbor."
In reviewing the visit, the Pontiff made special mention of his meeting with the world of culture at the Institute de France and the College des Bernardins: "I consider culture and its proponents to be the privileged vehicles of dialogue between faith and reason, between God and man."
The Holy Father said the second panel of the diptych was his three-day pilgrimage to Lourdes, "an emblematic place which attracts and fascinates every believer."
"Lourdes is like a light in the darkness of our groping to reach God," he said. "Mary opened there a gate towards a hereafter which challenges and charms us. Maria, porta caeli!"
Benedict XVI said he was "duty-bound" to participate in the jubilee celebrations, and that he came as a pilgrim.
The Pontiff celebrated two Masses in Lourdes. Some 190,000 pilgrims attended the Sunday Mass in the prairie that marked the 150th anniversary of the Marian apparitions, and some 70,000 people participated in today's Mass for the sick at Rosary Square.
"The two Eucharistic celebrations in Lourdes gave me an opportunity to join the faithful pilgrims," the Pope said. "Having become one of their number, I completed all four stages of the Jubilee Way, visiting the parish church, the cachot and the Grotto, and finally the Chapel of Hospitality."
"I also prayed with and for the sick who came here to seek physical relief and spiritual hope. God does not forget them, and neither does the Church," the Holy Father stressed. "Like every faithful pilgrim, I wanted to take part in the torchlight procession and the Blessed Sacrament Procession. They carry aloft to God our prayers and our praise."
"Lourdes is also the place where the Bishops of France meet regularly in order to pray and celebrate Mass together, to reflect and to exchange views on their mission as pastors," Benedict XVI added. "I wanted to share with them my conviction that the times are favorable for a return to God."
"May God bless France," the Holy Father said before he boarded the plane for Rome. "May harmony and human progress reign on her soil, and may the Church be the leaven in the dough that indicates with wisdom and without fear, according to her specific duty, who God is."