HAVANA -- In the first full day of a historic trip to this Communist-run nation, Pope Francis delivered both an appeal to the individual spirit of the Cuban people and a call for service in the absence of ideology.
The pope imbued his speeches with those messages at a Mass before tens of thousands, an evening prayer service and a meeting with Cuban youth. He also held private meetings with President Raúl Castro and the father of the Cuban revolution, Fidel Castro.
Francis began his day at Revolution Square by celebrating Mass near the plaza's huge image of revolutionary Ernesto "Che" Guevara, with Cubans packed together in the dense heat waving flags and snapping photos of him arriving in his iconic popemobile.See alsoText of pope's Havana MassSee alsoJesus, Che images face offSee alsoSpecial coverage: Pope Francis
In his homily at the Mass -- attended by Raúl Castro -- Francis urged service to people, not ideas.
"There is a kind of 'service' which truly 'serves,' yet we need to be careful not to be tempted by another kind of service, a 'service' which is 'self-serving,' " Francis, the first Latin American pope, said in his native Spanish.
In a gentle warning, the pope added: "There is a way to go about serving, which is interested in only helping 'my people,' 'our people.' This service always leaves 'your people' outside, and gives rise to a process of exclusion."
He went on to caution against slavish obedience to ideology, adding: "Service is never ideological, for we do not serve ideas, we serve people."
Later, Francis addressed a special evening prayer service at the Cathedral of Havana, where he referred to the "many sacrifices" the Cuban people have had to bear, and advised against mistaking unity with conformity.
"Unity is often confused with uniformity; with actions, feelings and words which are all identical," he said. "This is not unity, it is conformity. . . . Unity is a gift, not something to be imposed by force or by decree."
He broadened into a theme of hope for youth gathered at the Centro Cultural Padre Felix Varela, named for a Cuban priest who became an apostle for American immigrants in New York in the early 1800s.
"A path of hope calls for a culture of encounter, dialogue, which can overcome conflict and sterile confrontation. To create that culture, it is vital to see different ways of thinking not in terms of risk, but of richness and growth," the pope said. "The world needs this culture of encounter."
Leonardo Fernandez, 21, a college student, spoke to the gathering, reflecting his own wishes for the future of the island nation.
"What unites us is the hope of a future of profound changes and where Cuba will be a home for all of its children however they think and wherever they are," he said.
Fernandez also asked the pope to help them not get closed in by "the ideologies or the religions so that we can grow beyond the individualism and the indifference which are great defects of the Cuban routine."
Francis thanked Fernandez, adding "when I look at all of you, the first thing that comes into my mind and heart, too, is the word 'hope.' "
Elizabetta Pique, a journalist from Argentina who has known the pope for years and has written a biography of him called "Pope Francis: Life and Revolution," said it was clear he was subtly addressing Cuba's leaders.
"It's evident," Pique said, speaking in Spanish, "because neither can he come here to scold anyone. It's obvious he is sending a message that they should open" their society more.
But Georgetown University professor Eusebio Mujal-Leon, who has studied Cuban politics and the Catholic Church, said the pope has been "extraordinarily discreet if not incredibly quiet about making any reference to the internal Cuban situation."
"I'm actually a bit disappointed," he added.
But he said he thought the lack of pointed references to the situation could be part of a "top-down strategy of accommodating with the regime in the hopes of gaining greater space and tolerance for the Catholic church."
May Antonio Perez Garcia, 45, an artist and translator who attended the Mass, called the occasion momentous -- partly because it is the third time the government has allowed a pope to speak there.
Pope Benedict XVI visited in 2012, while Pope John Paul II was at the plaza in 1998.
Allowing three popes to speak here "in the past would have been impossible," he said in Spanish. "That the government has permitted three popes to give Masses in the plaza of Jose Marti, the principal place of speeches of the Communist ideology . . . is a symptom that the Castro dynasty simply has recognized how mistaken they have been."
Between his public appearances, Francis visited with Raúl Castro at the Palace of the Revolution, where the two men sat in conversation at a round table flanked by palm trees and the Cuban and Vatican flags.
Later, the pope met with Raúl's brother, former Cuban leader Fidel Castro, for an informal conversation at his home, according to Vatican spokesman Frederico Lombardi.
The pope and Fidel Castro, who brought the Communists to power in Cuba in 1959, exchanged books and apparently spoke about 40 minutes, Lombardi said.
Monday, Francis is scheduled to fly to Holguin, where he will celebrate Mass and bless the city before leaving for Santiago in the afternoon. There, he will meet with bishops at St. Basil the Great Seminary and pray at a shrine for Our Lady of Charity of El Cobre.
He departs Cuba for Washington D.C. Tuesday.