Who said "There's no such thing as a clean war."?

This quote is attributed to Frank Castle.

There's no such thing as a clean war. - Frank Castle

"There's no such thing as a clean war."

Frank Castle War

"Punishment is a language they understand."

"I'm not a hero. I'm a tool, sharpened and aimed."

"The only way to stop evil is to be better at it than they are."

"Mercy is for the living. The dead don't care."

"Some battles are worth fighting."

"Sometimes you have to become the monster to stop the monsters."

"Skynet sent me back through time to kill you."

"War teaches us the value of peace."