JORDAN PETERSON: No, you should be capable of it, but that doesn't mean you should use it. "Those who have swords and know how to use them but keep them sheathed will inherit the world."

It's very helpful for people to hear that they should make themselves competent and dangerous and take their proper place in the world.

Competent and dangerous?  Why dangerous?  

Because it's the alternative to being weak and weak is not good.

By dangerous that implies I should be ready to threaten someone to hurt somebody.

No, you should be capable of it, but that doesn't mean you should use it.  "Those who have swords and know how to use them but keep them she will inherit the world."  That's a way better way of thinking about it. There's nothing to you otherwise.  If you're not a formidable force, there's no morality In yourself control.  If you're incapable of violence, not being violent isn't a virtue.  Capacity for danger and the capacity for control is what brings about the virtue.  Otherwise, you confuse weakness with moral virtue.  I'm harmless, therefore I'm good.  No, that isn't how it works at all.  If you're harmless, you're just weak, and if you're weak you're not going to be good. You can't be because it takes strength to be good. It's very difficult to be good.