Our air conditioner quit last week, so I took it apart and spread the pieces all over the backyard. This caused me to realize two important facts. First, I am not a plumber and I have no idea how an air conditioner works. Second, most of the time you cannot tell whether a piece of electrical equipment is working or not based on how it looks. One needs some sort of diagnostic tool to make the proper assessment. When the plumbers showed up the next day, they brought their multimeter, found the bad component, and fixed the problem in ten minutes. That experience made me think that it would be great to have a similar diagnostic tool to check on our spiritual health and see how we are doing. Fortunately, God has already supplied one.