What that doesn't kills, makes one stronger.
"If you have to do it, KILL him. If not, don't even think about it."
Why? By exposing someone/thing to a threat or danger, but not killing the person, only allows the person to be aware of such things, and most resilient.
Too many times in life, we meet things/people in life who create a sudden realisation of pain. Probably not every time physically, but also mentally and emotionally. But what that we survive through, would bring us to the next level of resistance if we were be able to live through it.
Behind every successful man, lies failures.
Behind every rich man, lies a day of hunger.
Behind every strong man...
... lies a tear-jerking incident.
What's behind you?