You can't truly call yourself "peaceful" unless you're capable of great violence.

If you're not capable of violence, you're not peaceful. You are harmless.

I've always loved Miyamoto Musashi's adage from The Art of War, "It's better to be a warrior in a garden than a gardener in a war."

It sounds sage and judicious.

But to be honest, I didn't quite comprehend its meaning until I started training Brazilian Jiu-Jitsu.

When confronted in hand-to-hand combat, you quickly realize how helpless you are. If you back down from confrontation because you can't handle a physical altercation, that's not good.

Counterintuitively, being capable of violence has made me more peaceful. With those skills in my arsenal, I can rely on them to de-escalate a situation or handle it if it does become violent.

The essence of the sentiment is that instead of being unable to do things, you should become capable enough to choose not to do things.

"A harmless man is not a good man. A good man is a very dangerous man who has that under voluntary control." - Jordan Peterson

The more capable you are, the more ways you can act. The more ways you can act, the more ways you can act virtuously.