Benedict made the comments to Catholic social workers, health providers and others after celebrating Mass before an estimated 400,000 people in Fatima. The central Portuguese farming town is one of the most important shrines in Christianity, where three shepherd children reported having visions of the Virgin Mary in 1917.
Benedict's visit to Fatima on the anniversary of the apparitions was the spiritual centerpiece of his four-day visit to Portugal, which ends Friday. It was cast by Vatican officials as evidence that he had turned a page in weathering the abuse scandal, which has dogged him for months.
The Vatican spokesman, the Rev. Federico Lombardi, pointed to the turnout in Fatima and said it was "very beautiful and encouraging" that pilgrims hadn't been deterred in expressing their faith despite months of revelations in Europe about priests who molested children and bishops and Vatican officials who turned a blind eye.
The faithful understand "the capacity of the church to effectively overcome - via conversion, penance and prayer - the dimension of real sin there is in our community," Lombardi said.
Benedict himself admitted to the "sins within the church" on the first day of the trip, his most explicit admission of Church culpability in the scandal. By Thursday, however, he had moved on to stressing core church teachings in the largely Roman Catholic country, where abortion on demand has been available since 2007 and where Parliament in January passed a bill allowing same-sex marriage. In addition, a judge in 2008 made it easier to obtain divorce even when one spouse objects.
Benedict told the gathering of lay Catholics that he appreciated their efforts fighting abortion and promoting the family based on the "indissoluble marriage between a man and woman" - the Vatican's way of expressing its opposition to divorce and same-sex unions.
Such initiatives "help respond to some of the most insidious and dangerous threats to the common good today," he said. "Alongside numerous other forms of commitment, such initiatives represent essential elements in the building of the civilization of love."
The admonition was a break of sorts from the continuous message Benedict has delivered in Portugal about the suffering of the world and church - a message which resonates in Fatima, where the sick and infirm flock seeking remedies for ailments.
In a special message to the sick during Mass, Benedict urged them to take heart, saying they should "overcome the feeling of the uselessness of suffering which consumes a person from within and makes him feel a burden to those around him."
"In suffering, you will discover an interior peace and even spiritual joy," he said.
His message struck a chord with many in the huge gathering, among them elderly and infirm people who, with their heads bowed, fingered rosaries.
Aurora Clemente, a 65-year-old cook from Portugal's northeastern tip, close to the border with Spain, said she had been coming to Fatima on May 13 for more than 30 years.
"Fatima makes miracles. When my son was seriously ill, I prayed to the Virgin of Fatima and he survived," she said.
"I find it very moving here. For me, this is the most beautiful place in the world," she said, sitting beneath a red umbrella on the fringe of the crowd.
Like Lourdes in France, Fatima attracts millions of pilgrims a year seeking cures. One of the rituals pilgrims perform at Fatima involves casting replicas of body parts - eyes, lungs, hearts - on sale at local shops into a big bonfire while reciting a prayer asking for healing.
Pope Paul VI visited Fatima in 1967. Pope John Paul II - who was shot in St. Peter's Square on May 13, 1981 - came three times before his death, believing that the Virgin's "unseen hand" had saved him.
During his third and final visit in 2000, the Vatican announced the "third secret" of Fatima: the third part of the message the Virgin is said to have told the three children: a description of the assassination attempt on Pope John Paul II.
The first two secrets of Fatima were said to have foretold the end of World War I and the outbreak of World War II and the rise and fall of Soviet communism.
After the third secret was revealed, the Vatican essentially implied the Fatima case was closed. But on Thursday, Benedict said its message continued to be relevant.
"We would be mistaken to think that Fatima's prophetic mission is complete," Benedict said in his homily during the Mass. Lombardi was asked if such comments were merely an effort to keep Fatima's fascination relevant to the faithful at a time when the Cold War and John Paul's assassination attempt are no longer front-burner issues.
"The term 'prophetic' doesn't mean an announcement of concrete facts that one sees in a crystal ball but rather knowing how to read history and events in the light of faith," Lombardi said.