From YOUCAT, fact 397:
397: What does Jesus think about nonviolence?
Jesus places a high value on nonviolent action. He commands his disciples: “Do not resist one who is evil. But if any one strikes you on the right cheek, turn to him the other also” (Mt 5:39).
He rebukes Peter, who wants to defend him with force: “Put your sword into its sheath (Jn 18:11). Jesus does not call his disciples to take up weapons. He remains silent before Pilate. His way is to take the part of the victims, to go to the Cross, to redeem the world through love, and to call the pacemakers blessed. Therefore the Church, too, respects people who for reasons of conscience refuse to be part of the armed services but place themselves at the service of society in some other way.