Christ lives in us, in fact he is the life by which we live. "Your old life is dead. Your new life, which is your real life—even though invisible to spectators—is with Christ in God. He is your life. When Christ (your real life, remember) shows up again on this earth, you'll show up, too—the real you, the glorious you." (Col 3:3-4).
Ever since we were young we have be trying to understand ourselves, to know the kind of person we are, why we act or react in certain ways and why we find it difficult to do certain things. As we grow we learn about ourselves and our nature, we come to know who we are. When we became born again our nature was change, we became a new person because our old life died and we were impacted with a new life, this new life is Christ. Now that we have been reconstituted, we need to start learning about our new self or rather about the indwelling Christ because our new self is Christ (we are reconstituted according to the status of Christ). We have to acknowledge that the 'self' we use to know is dead and should look forward to knowing this new self which is Christ in us.
But the question is how do we know the indwelling Christ? Well, it the same way we know our old self. We know our old self by living by our old life and trying to understand ourselves. So also we would know the indwelling Christ by trying to live by the life of the indwelling Christ and learning why he act in certain ways and experience difficulty in doing some certain things. As we live by that life of Christ we would see Christ doing some things through us and through this way we learn about the indwelling Christ. We no longer have to depend on historical account to know the kind of person Christ is but we can now know him by watching him live out his life through us.