Washington — Pope Francis quietly but forcefully made his priorities clear during his first full day in the United States on Wednesday, urging in a pair of speeches a renewed emphasis on tackling global poverty, confronting climate change, caring for migrants and providing a welcoming church that is pastoral rather than doctrinaire.

President Barack Obama welcomed the spiritual leader of the world’s 1.2 billion Roman Catholics with the fanfare of trumpets and a show of solidarity, escorting him onto a red-carpeted stage at the South Portico of the White House and praising his moral authority that “comes not just through words but also through deeds.”

The pope arrived at the White House in his modest Fiat and later drove slowly in his open-air popemobile past a jubilant crowd of 11,000 people assembled behind metal barriers on the Ellipse, juggling small flags of the Holy See and mobile phones as they craned for a glimpse of the pontiff or a brief touch on the head. The papal motorcade later made its way to the Cathedral of St. Matthew the Apostle, where Francis spoke to a gathering of nearly 300 bishops from around the country.

In remarks delivered in English at the White House and in a speech in Italian to the leaders of the Catholic Church in the United States, the pope kicked off a six-day U.S. visit with a message that praised the country’s devotion to freedom of liberty and religion even as he cautioned that the nation’s vast resources demanded a deep sense of moral responsibility.

Speaking to his “brothers” at the cathedral where John F. Kennedy was eulogized in 1963, the pope was warm and encouraging but also spoke clearly and with simple language that was unmistakable in its emphasis. He praised the bishops for their work on behalf of immigrants and for the first time praised their “courage” in handling the church’s sex-abuse scandals.

“I am also conscious of the courage with which you have faced difficult moments in the recent history of the Church in this country without fear of self-criticism and at the cost of mortification and great sacrifice,” the pope told the bishops.

Like his predecessors, he urged the bishops not to remain silent toward the “innocent victim of abortion.” But he mentioned the highly charged issue only as the first in a long list of other matters, including children who die of hunger and bombings, immigrants who “drown in the search for a better tomorrow,” the elderly or sick, the victims of terror, war and drug trafficking, and an environment “devastated by man’s predatory relationship with nature.”

Speaking to bishops who have not always agreed with his spiritual emphasis, the pope said that he had “not come to judge you or to lecture you.” But he nonetheless offered what he called “reflections which I consider helpful for our mission,” including a warning against yielding to “the temptation to become notaries and bureaucrats.”

Among his reflections was an admonition to focus on pastoral duties. He said the “style of our mission” should make parishioners feel that the message was meant for them. “Be pastors close to people, pastors who are neighbors and servants,” he instructed.

“Know that the pope is by your side,” he said “The pope supports you. He also puts his hand on yours, a hand wrinkled with age, but by God’s grace still able to support and encourage.”

Francis also pressed his case for particular attention to immigrants and refugees as a primary responsibility of the church. Speaking of the recent surge of migration from Latin America, he acknowledged that parishes may be “challenged by their diversity.”

“But know that they also possess resources meant to be shared — so do not be afraid to welcome them,” he said. “I am certain that, as so often in the past, these people will enrich America and its church.”

Later in the afternoon, the pope traveled to the campus of Catholic University to celebrate his first Mass in the United States in front of an estimated crowd of about 25,000 people, and to canonize Junípero Serra, a Franciscan who founded missions across California in the 1700s.

The pope returned to his open-air popemobile to greet the enthusiastic crowd before entering the Basilica of the National Shrine of the Immaculate Conception, the nation’s largest Roman Catholic church, to deliver the homily.

“Junípero sought to defend the dignity of the native community,” the pope said, speaking in Spanish, “to protect it from those who had mistreated and abused it — mistreatment and wrongs which today still trouble us, especially because of the hurt which they cause in the lives of many people.”

The pope used the ceremony, the first canonization of a saint on American soil, to underscore his message on immigration. He implored the American public and the church’s bishops to be welcoming of migrants escaping danger and to immigrants seeking a new and better life.

In his remarks, he singled out Serra for defending the dignity of Native Americans and protecting them, a claim that many Native Americans dispute.

“The church, the holy people of God, treads the dust-laden paths of history, so often traversed by conflict, injustice and violence, in order to encounter her children, our brothers and sisters,” he said.

Olga Herrera, 30, and eight other members of a young-adults group at St. Camillus Catholic Church of Silver Springs, Maryland, all of them from Guatemala, cheered when Pope Francis accepted the proclamation made on behalf of Serra’s sainthood.

While he was at the White House, the pope waded into two of America’s most highly charged political debates, praising the United States as a nation of immigrants and offering a strikingly explicit endorsement of Obama’s regulatory program to fight climate change. With Obama sitting next to him on the stage, the pope skirted lightly past disagreements about abortion and same-sex marriage.

Ahead of the pope’s visit, some wondered whether he would dwell on the excesses of capitalism and the role that free enterprise plays in economic inequality and poverty. He did not, spending much more time offering a robust endorsement of the president’s policies on the environment.

“Mr. President,” Francis said, speaking in English despite his discomfort with the language, “I find it encouraging that you are proposing an initiative for reducing air pollution. Accepting the urgency, it seems clear to me also that climate change is a problem which can no longer be left to a future generation. When it comes to the care of our common home, we are living at a critical moment of history.”

Devoting more of his address to that issue than to any other topic, the pope said there was still time to heal the planet for its children. “To use a telling phrase of the Rev. Martin Luther King, we can say that we have defaulted on a promissory note and now is the time to honor it,” he said.

In welcoming the pope for his first trip to the United States, Obama thanked him for his help in facilitating the restoration of diplomatic relations with Cuba and hailed him for speaking out for the world’s most impoverished. Facing stiff domestic resistance to his plans to crack down on power plants and other sources of greenhouse gases, Obama welcomed the pope’s focus on climate change.

“Holy Father, you remind us that we have a sacred obligation to protect our planet — God’s magnificent gift to us,” he said. “We support your call to all world leaders to support the communities most vulnerable to a changing climate and to come together to preserve our precious world for future generations.”

The president also associated himself with the pope’s focus on the needy, the sick and the dispossessed. “You shake our conscience from slumber,” he said. “You call on us to rejoice in good news and give us confidence that we can come together, in humility and service, and pursue a world that is more loving, more just and more free.”

The ceremony brought together two men with starkly disparate backgrounds and yet commonalities that have united them at this moment in history, a community organizer from Chicago and a priest from Argentina, both presenting themselves as champions of those without any. Although they first met last year at the Vatican, their appearance together Wednesday carried a visual and possibly a political power that solidified the impression of a secular-theological alliance.

The pope, whose sometimes strident critique of global capitalism has drawn rebukes from Catholics in the United States, seemed intent on demonstrating affinity for a country he has never before visited in his 78 years. He praised the United States for its defense of religious freedom and ended his remarks by declaring “God bless America.”

With unmistakable meaning, the pope also noted the country’s origins at a time when critics of illegal immigration are pushing to build a wall at the border. “As the son of an immigrant family, I am happy to be a guest in this country, which was largely built by such families,” Francis said.

After he left the White House, the pope went to the Cathedral of St. Matthew the Apostle, where the crowd swelled so deep that for many the only sign of the pope’s arrival was a loud cheer echoing through nearby streets.

“I think I saw some white — hard to tell,” one man said moments later, as he left Jack’s Fresh, a salad bar and grill near the cathedral. A crowd of more than 50 people inside pressed against windows facing the cathedral and stood eagerly on chairs to get a better view.

As the pope entered the cathedral, the rector, Monsignor W. Ronald Jameson, who greeted him at the door threw his arms open wide. As he walked down the church’s center aisle between rows of bishops in pink zucchettos, some of them held up phones and cameras to take pictures.

Archbishop Alexander Sample of Portland, Oregon, posted on Twitter from his seat in the pews: “Pope Francis has arrived!”

Downtown Washington was wrapped in an expansive security blanket Wednesday morning, with roads near the White House blocked by police vehicles, snow plows and other vehicles, while security officers in police and military uniforms turned away morning traffic and patrolled every block. In the predawn darkness, a stream of Catholics and non-Catholics alike surged on foot toward checkpoints in hopes of catching a glimpse of the 266th pope.

As they waited to pass through metal detectors at Lafayette Square, they could hardly avoid the blaring words of a lone protester with a sign declaring “The Pope is an Antichrist” and a working bullhorn. “There is no peace for the wickedness,” he shouted. “The end has come.”

The White House itself was more welcoming, with Vatican flags flying alongside American ones and row after row of folding chairs set up on the South Lawn for guests. Among those on hand were Joe Biden, the nation’s first Catholic vice president, and a host of dignitaries from the church, Cabinet and Congress as well as everyday believers.

Francis, who ascended to the papacy in 2013, has infused the church with new energy and purpose. He has earned the nickname “the people’s pope” with a message focused on helping the poor and the disadvantaged even as conservatives worry that he has diluted Catholic commitments toward ending abortion and defending traditional marriage.

Surveys show broad support among Americans for the direction he is taking the church. A New York Times/CBS News poll found that 41 percent of Americans had a favorable view of Francis, compared with 8 percent who had an unfavorable view, a higher level of support than his predecessor, Pope Benedict XVI, ever had among Americans in that survey. The same poll found that 63 percent of American Catholics approved of Francis, about 20 percentage points higher than Benedict’s rating at his peak.

In a way, though, with so many undecided, Francis is still introducing himself to his American flock, using his six-day, three-city tour to showcase his priorities and take the measure of parishioners in this country.

Francis is only the fourth pope to visit the United States while in office and the third to visit Washington. Indeed, presidents and popes rarely met until recent decades. Woodrow Wilson became the first sitting president to meet a pope when he visited Pope Benedict XV at the Vatican in 1919.

Since Dwight D. Eisenhower, however, every president has met a pope while in office. Jimmy Carter was the first to host one at the White House when Pope John Paul II came in 1979. George W. Bush became the second when Benedict XVI visited in 2008. Bush, who met with popes inside and outside the White House more than any of his predecessors, also was the first president to attend a papal funeral when John Paul died.

On Thursday morning, Francis will become the first pope to address a joint meeting of Congress, at the invitation of Speaker John A. Boehner, a Catholic Republican from Ohio. The demand for tickets has been so high that congressional officials imposed unusual limits on many who normally have rights to the House floor, and about 50,000 people are expected to watch on large televisions on the West Lawn of the Capitol.

After a meeting with indigent, homeless and other disadvantaged people served by Catholic Charities, the pope will head to New York for a two-day visit and later to Philadelphia.