Well, it is what one carries along with them; be it an animal or a human or etcetera.

 

As the car itself is you, whatever or whomever you take with you will be your "passenger".

 

Remember too, that as you are inside of this car (shell/Body), all things inside reflect internal issues present on the mind.

 

Therefore, it is important to note: Not all passengers are pleasant.

 

As you are the driver of your vehicle (body), whatever or whomever you take along with you is your responsibility.

 

and again, not all passengers are pleasant, so to make your sojourn smoothe, you must try to work things out with your passenger.

 

Although they are going along for the ride, you are the one who ultimately will let them in.

 

This aspect of the "passenger" presence will be with you for the mind's sake.  To weigh the need to understand what is bothering the intellect.

 

Again, I speak of the internal merit of the condition of the mind, here, that concerns another... called the "passenger".

 

Again, it is whatever you carry in your thoughts that is most prevalent.