I've heard about firebreaks, if that's what they call it. But the usual way to fight fire is not with fire. So if someone is going to make up saying about something it should be clearer. Like, fight wild fire with a small line of fire to clear the brush, and go on to say, fight a house fire with a water hose or baking soda. Doesn't have the same ring, but it's truer.Maybe that expression is about when firefighters start a line of small fires to cause forest fires to burn out. The line of smaller fires burns up everything flammable. The forest fire has nowhere left to go.