Old fire station proverbial route
When you help someone out of a fire, you are helping someone who is in trouble. Firefighters, of course, sometimes literally help someone out of a burning house. But there doesn't have to be a fire involved when you use this expression. You can also say that you are on fire. Then you don't literally mean that you are in the fire, but that you are in trouble. So "fire" in these proverbs symbolizes "trouble.