Spending more than three hours Jan. 15 at the parish of St. Mary in the Setteville neighbourhood, Pope Francis had the same basic message for the children and youths as he did for the parish as a whole: "Christian witness is done with three things: words, the heart and the hands."

As is his custom for parish visits in the Diocese of Rome, Pope Francis arrived in the late afternoon and held separate meetings with the children and teenagers from the religious education program and Scout groups; with the parents of the 45 babies baptized in the parish over the past year; with a group of parishioners who are sick or have disabilities; and with the parish council and more than 100 parishioners active in parish activities.

Before celebrating Mass, he heard the confessions of four parishioners. The Vatican press office said they were the young couple who care for the 50-year-old assistant pastor, who has amyotrophic lateral sclerosis; a young man from the parish post-confirmation program; and the father of a sick child.

In response to the questions of the parish young people, Pope Francis insisted, "If I say I am Catholic and go to Mass every Sunday with my parents, but I don't speak (about Jesus), I don't help my grandparents, don't help the poor, don't visit the sick, then it is not witness and it is useless."

"It is nothing other than being a parrot-Christian – words, words, words," he said. Christian witness requires action.

Celebrating Mass with a standing-room-only congregation and hundreds of people watching on jumbo screens outside, Pope Francis focused on the witness of St. John the Baptist, who pointed to Jesus as the Messiah.

Many of the first people to follow Jesus, including some of the first apostles, had been followers of St. John the Baptist. "How did they meet Jesus?" the Pope asked. "Because there was a witness," who told them Jesus was the one. "It is the same in our lives."

Faith is not like being "the fan of a team" or "having a philosophy" or just following a set of rules, he said. "Being a Christian is first of all giving witness to Jesus."

Christianity has spread throughout the world because people have given witness in word and deed to Jesus as saviour. Sometimes, he said, the witness was given in small ways and other times through the great witness of martyrdom.

"The apostles didn't take a course to learn to be witnesses of Jesus," the Pope said. Instead, they followed him and listened to him and tried to imitate him.

"But they were sinners," he said. "All 12 of them" as the Gospels recount. They experienced pride and jealousy and "when Jesus was taken, they all ran away."

"Peter – the first Pope – denied Jesus," he said. But they were witnesses to Jesus because they recognized their sinfulness and that their salvation came not from anything they did, but from Jesus' love and sacrifice. "They allowed themselves to be saved."

"Being a witness does not mean being a saint, but being a poor man or poor woman who says, 'Yes, I am a sinner, but Jesus is lord and I will try to witness to him every day and to correct my life and follow the correct path,'" he said.

One sin the Gospels did not accuse the apostles of, the Pope said, is gossip. "They didn't speak ill of each other."

"Do you want a perfect parish?" Pope Francis asked the people. "Then no gossip. None. If you have something against another, tell him or her directly."

The Pope returned to the theme at the end of Mass. After final blessing, he told them, "Don't forget to pray for me and no gossip."