270 I ask Christians who remain hesitant on this point, and those tempted to yield to violence in any form, to keep in mind the words of the book of Isaiah: “They shall beat their swords into plowshares” (2:4). For us, this prophecy took flesh in Christ Jesus who, seeing a disciple tempted to violence, said firmly: “Put your sword back into its place; for all who take the sword will perish by the sword” ( Mt 26:52). These words echoed the ancient warning: “I will require a reckoning for human life. Whoever sheds the blood of a man, by man shall his blood be shed” ( Gen 9:5-6). Jesus’ reaction, which sprang from his heart, bridges the gap of the centuries and reaches the present as an enduring appeal.
Source: Fratelli Tutti (Vatican.va)