ROME – In a sense, every papal liturgy in St. Peter’s Basilica has symbolic value, but rarely was that symbolism more overtly on display than on Sunday, when Pope Francis led a Mass for the Catholic Church’s Jan. 14 World Day of Migrants and Refugees.

Obviously intended to drive home the message that migrants are refugees and not just abstractions for Catholicism, but part of its family of faith, there were representatives of 49 nations on hand in the basilica, including 2,000 immigrants and refugees from the Philippines, more than 1,200 Ukrainians, 800 Romanians, 650 Indians, as well as groups from Lebanon, Syria, Madagascar, Sri Lanka, Capo Verde, and China.

Speaking directly to those groups, Francis said on Sunday, “This year, I wanted to celebrate the World Day of Migrants and Refugees with a Mass that invites and welcomes you especially who are migrants, refugees and asylum seekers.”

“Some of you have recently arrived in Italy,” the pope said, “others are long-term residents and work here, and still others make up the so-called ‘second generation’,” calling for an attitude of “welcoming, knowing and acknowledging” the other.

In his homily, Francis acknowledged that today’s rising numbers of immigrants and refugees often generate fear in host societies, saying those anxieties are “fully comprehensible from a human point of view.”

“Having doubts and fears is not a sin,” Francis said.

“The sin is to allow these fears to determine our responses, to limit our choices, to compromise respect and generosity, to feed hostility and rejection,” he said.

“The sin is to refuse to encounter the other, the different, the neighbor, when this is in fact a privileged opportunity to encounter the Lord,” he said.

The important thing, Francis said, is “to overcome our fears so as to encounter the other, to welcome, to know and to acknowledge him or her.”

Francis began by laying out a challenge to both immigrants and the host societies receiving them.

The pontiff called on new arrivals “to know and respect the laws, the culture and the traditions of the countries that take them in,” and, he said, it’s also important to “understand their fears and apprehensions for the future.”

For host societies, Francis urged them “to open themselves without prejudice to their rich diversity [of migrants and refugees], to understand the hopes and potential of the newly arrived as well as their fears and vulnerabilities.”

The music for Sunday’s Mass was provided by a youth choir from Turin, joined for the occasion by several immigrant singers, and it supplied a more upbeat and contemporary sound than is often associated with solemn liturgies in St. Peter’s.

Prayers of the Faithful were read by migrants and refugees from Nigeria, China, India, Syria, Ukraine, Ethiopia, and the pope was assisted during the Mass by seminarians from the Scalabrinian missionaries from Indonesia, Vietnam, the Philippines, Congo, Mexico, Brazil and Guatemala.

It was actually the order’s founder, Blessed Giovanni Battista Scalabrini, who proposed that the Vatican set up a special office for migrants and refugees in 1912, concerned about the rising tide of nationalism in Europe and the displacements those forces were causing both at home and abroad.

Earlier in August, Francis released a message for the World Day of Migrants and Refugees, in which he recalled that this been a priority for him from the beginning of his papacy, expressed in his first trip outside Rome to the Italian island of Lampedusa in July 2013.

The pope also noted that he’s created a new Dicastery for Promoting Integral Human Development with a special section for migrants, displaced people, refugees and victims of human trafficking, which he directs personally.

He centered the message around four verbs with regard to migrants and refugees: “Welcoming, protecting, promoting and integrating.”

Among other points, he stirred controversy by asserting that we must “always prioritize personal safety over national security,” in what was taken as a criticism of increasingly restrictive policies in some nations often justified by security considerations.

The pontiff also lent his support to two Global Compacts scheduled to be drafted and adopted by the United Nations in 2018, one on migrants and the other on refugees.

Although Francis, the son of Italian immigrants in Argentina himself, is particularly concerned with people on the move, the World Day of Migrants and Refugees has much deeper roots in the Catholic Church.

The Jan. 14 observance was established in 1914 by Pope Pius X, who was concerned about a mounting refugee crisis in Europe driven by World War I. The United Nations did not establish its own World Refugee Day until 2000.

Also in 1914, the Vatican issued the decree Ethnografica studia, which dealt for the first time with the question of clergy becoming involved in the care of migrants. It stressed the responsibility of the local church to assist immigrants, and suggested that local clergy be given specific linguistic, pastoral and cultural preparation.

Later in the day, during his noontime Angelus address, Francis announced that due to unspecified “pastoral motives,” he’s transferred the World Day of Migrants and Refugees to the second Sunday of September, with the next one set for Sept. 8, 2019.

Some 460 cardinals, archbishops and bishops, as well as priests concelebrated the Mass on Sunday with Francis, with his main concelebrants being Cardinal Peter Turkson, Prefect of the Dicastery for Promoting Integral Human Development; Archbishop Angelo De Donatis, the Vicar General for Rome; and Bishop Guerino Di Tora, Auxiliary Bishop of the Diocese of Rome.