The Importance of the Holy Ghost
Deep sea divers enter the water with tanks on their backs. These tanks contain oxygen. The purpose of these tanks strapped to their backs is so that they can make it in a foreign world. Water is not their natural habitat; it's not the normal place for them to live, so in order for them to survive in this foreign world of water, they need to be connected to a life source from their real world. In other words, if they get disconnected from the air from this world, they won't last long in that world. Their connectedness is the key to their survival because they weren't meant to live in water. So they borrow from this world in order to live in that world.
That life source in the life of a Christian is the Holy Ghost (Spirit). God has given the Christian a life source because this world to the Christian is foreign territory. In order to live here and make it, you need to be connected to a life source from your real world. If you get disconnected from the life source from your real world, you won't make it in this world as a Christ follower. You'll be gagging for air that this world doesn't offer because it's foreign territory. This life source comes through the indwelling of the Holy Ghost.
Shalom!
Shalom!