"Good politics is at the service of peace" will be the theme for the Jan. 1 commemoration and for the message Pope Francis will write for the occasion.
Following the Francigena Way, an ancient pilgrims' path, a group of about 300 synod participants and young people from Rome parishes headed to St. Peter's Basilica to pray at the apostle's tomb.
Honduran Bishop Jose Antonio Canales of Danli said that, given what is going on in his country and throughout Central America, he had to walk in the "Share the Journey" campaign of Caritas Internationalis.
Speaking to the Synod of Bishops on behalf of Belgium's bishops' conference, a bishop said he was sure some young married men would become priests if they were asked.
"Is it right to hire a hit man to solve a problem? No, you can't. It's not right to take out a human being, a small one, too, in order to fix a problem. It is like hiring a professional killer," the pope said.