ROME – Marking the feast of Christianity’s original martyr, Pope Francis on Tuesday said St. Stephen’s story illustrates that the message of Jesus always “challenges worldly religious power, and provokes consciences.”

Jesus’ message, Francis said, “is upsetting, and it upsets us … after his coming, we have to convert, to change mentalities, to stop thinking the way we did before.”

The day after Christmas is designated on the Catholic calendar as the feast of St. Stephen, a figure from the New Testament presented in the Acts of the Apostles as a deacon whose preaching of the new Christian faith aroused hostility from the religious leadership of the day and who was eventually stoned to death on charges of planning to destroy the Jewish temple in Jerusalem.

Stephen is celebrated as the first martyr, or the “protomartyr,” of the Church.

Francis’s remarks came during noontime Angelus remarks in Rome. The pontiff said that at first glance there may not seem much of a link between the birth of Christ and the story of St. Stephen, but in reality, he argued, the connection is “very strong.”

As the protomartyr, Francis said, Stephen gave his life and spirit to the new faith.

“He believed strongly and he professed the new presence of God among people,” Francis said. “He knew that the true temple of God is now Jesus, the eternal word who came to live amidst us, who became like us in everything but sin.”

The faith, Francis said, included forgiving those who wronged him – words, Francis said on Tuesday, “made possible only because the Son of God came to the earth, and died and rose again for us.”

“Prior to those events,” Francis said, such expressions of total forgiveness despite the wrongs suffered would have been “humanly unthinkable.”

The faith elicited in Stephen both a willingness to give up his life for it and for others, which, the pope said, invites contemporary Christians to “a double attitude of truth in the Father and love for others.”

“It’s an attitude,” the pope said, “that transforms one’s life and renders it more beautiful and fruitful.”

Among other points, Francis said the reconciliation brought by Christ “removed every conflict and resentment.”

In an extemporaneous touch that may reflect bruising internal debates within Catholicism over the past year, the pope said, “We all know what an ugly thing resentment is … they do much harm, much harm.”

This year, Francis did not use the occasion of St. Stephen’s feast to reflect on contemporary Christian martyrdom, which was his focus last year.

“Even today the Church, to render witness to the light and the truth, is beset in various places by hard persecutions, up to the supreme test of martyrdom,” Francis said on Dec. 26, 2016.  “How many of our brothers and sisters in the faith suffer abuses and violence, and are hated because of Jesus!”

After invoking the blessing of peace upon the crowd gathered in St. Peter’s Square on Tuesday, Pope Francis used the occasion to thank all those who sent him Christmas greetings.

“In these weeks, I’ve received lots of Christmas messages,” he said. “Since it’s not possible for me to respond to each, I express today to everyone my feelings of thanks, especially for the gift of prayer,” he said.

Tomorrow, Francis is scheduled to hold his usual Wednesday General Audience, his reflections for which in this period are being dedicated to the elements of the Mass.

On New Year’s Eve, Francis will offer a noontime Angelus address, and late that afternoon will preside over the traditional vespers service in thanksgiving for the year coming to a close. On New Year’s Day, Francis will celebrate a Mass honoring Mary as the Mother of God, followed by yet another Angelus.

Traditionally, the Vatican’s holiday season is said to wrap up on Jan. 6 with the feast of the Epiphany, when Francis will once again lead a Mass in the morning followed by an Angelus. Informally, however, it’s usually considered to extend through the pope’s annual speech to the diplomatic corps accredited to the Vatican, in which the pontiff lays out his foreign policy priorities for the year to come.

This year, that speech to diplomats will be held on Monday, Jan. 8.