Hire and Fire

As we've been looking to hire someone at church, I'm still convinced of my theory on hiring and firing which I began developing during my days at Nebraska Wesleyan University while being shaped by Rich Patrick... still one of my favorite professors ever.

Simply stated: You should never need to fire someone that you hire.

More completely stated: If you do your part and diligently interview, hire and then manage your new employee correctly, you should never have to fire them. If you do have to fire them it is not because of the employee's lack of knowledge, skills or abilities. Instead, it is because of your failure to accurately assess these failures before you made the decision to hire them. Or because you are unable to correctly motivate and challenge them so that they continue to perform for you while feeling completely satisfied by the job they were hired to do.

Most people think my theory is wrong at first, but after thinking about it for a while they agree. What do you say?