Then they came and laid hands on Jesus and took Him. And suddenly, one of those who were with Jesus stretched out his hand and drew his sword, struck the servant of the high priest, and cut off his ear. But Jesus said to him, “Put your sword in its place, for all who take the sword will perish by the sword. Or do you think that I cannot now pray to My Father, and He will provide Me with more than twelve legions of angels?”
Matthew 26:51-53
If you take a quote out of context (‘those who take the sword will perish by the sword’) then you can actually read it as a warning to all the unrighteous who raise their swords that they themselves will be overtaken by the sword of the righteous. The existing order of things says: criminal violence must be answered with force.
But if you look at the phrase in its entirety (‘Or do you think that I cannot now pray to My Father, and He will provide Me with more than twelve legions of angels’) then you are met with a completely different meaning. If He wanted protection He would, undoubtedly, receive it from above. But He does not require protection by means of injuring or killing people (‘Put your sword back in its place’) — and He warns against it: ‘all who take the sword will perish by the sword’ — not the righteous, not the unrighteous, but everyone who took the sword. The sword by which they die will not be the sword of their enemy, and not even the sword of the Heavenly Father, but their own sword: when we take it in our hands we cross the line that Christ commanded us not to cross (‘Love your enemies’). We are killing our own souls with the sword.