MANILA—Pope Francis waded into the debate over freedom of expression following the attacks in Paris, saying that killing in the name of religion is an “aberration,” but adding that those who deride other faiths can expect to provoke a strong—even violent—response.

Speaking in reference to last week’s assault on French publication Charlie Hebdo that left 12 dead, the pope said that “no one can kill in the name of God. This is an aberration.”

He added, however, that “there is a limit to freedom of expression.” The pope offered a colorful example, referring to a hypothetical case in which someone insults his mother. (Latest: Pope Francis Presses Social Justice Agenda in the Philippines)

“One cannot react violently, but if [someone] says something bad about my mother, he can expect a punch. It’s to be expected,” the pontiff said. “There are a lot of people who speak badly about other religions. They make fun of them. What happens is what happens with my friend [who insults my mother]. There is a limit.”

The pope made the comments during an in-flight news conference from Sri Lanka to Manila, where he took up the second leg of a weeklong tour of Asia. He was greeted at the airport by President Benigno Aquino III and a performance by hundreds of jeans-clad young people. People cheered the pope’s motorcade to the residence of the apostolic nuncio.