Remembering the Holocaust and its victims is not only an act of solidarity but also serves as a warning to humanity that such horrors could happen again, Pope Francis said.

Unable to preside over Mass on the Sunday of the Word of God because of a recurring bout of sciatica, Pope Francis’ homily was read by Archbishop Rino Fisichella, head of the Pontifical Council for Promoting New Evangelization, which coordinates the annual celebration.

Marking the Treaty on the Prohibition of Nuclear Weapons coming into force Jan. 22, Pope Francis encouraged nations to work toward a world free from all nuclear arms.

As Joe Biden prepared to be inaugurated as the 46th U.S. president, Archbishop José H. Gomez of Los Angeles, president of the U.S. Conference of Catholic Bishops, expressed hope the incoming administration “will work with the church and others of goodwill” to “address the complicated cultural and economic factors that are driving abortion and discouraging families.”

Joe Biden became the second Catholic to be inaugurated as president of the United States Jan. 20, giving some U.S. Catholics and their religious leaders a reason to rejoice and others to fear more access to abortion under his leadership.

In his inaugural address Jan. 20, President Joe Biden said he is committed with his “whole soul” to bring this country together.

Pope Francis prayed that President Joe Biden would work to heal the divisions in U.S. society and promote human dignity and peace around the globe.

With “social injustice, division and conflict” threatening the common good, people need to rediscover and recommit to the vision of the Rev. Martin Luther King Jr. to work nonviolently for harmony and equality for all, Pope Francis said.

For a variety of reasons, “especially in relation to the political situation” in the United States, the Legionaries of Christ university in Rome will not honor Father Frank Pavone, national director of Priests for Life, said the head of the university’s bioethics faculty.

Both Pope Francis and retired Pope Benedict XVI have received the first dose of the vaccine against COVID-19 after the Vatican started vaccinating its employees and residents Jan. 13.