'To conduct an exhaustive study' means to do research on everything relevant to something so thoroughly that it is known inside out. It's also important in our Christian lives to study ourselves and discover what we are lacking. For instance, when your co-worker was praised by your boss you have to check if you rejoiced together with him or did you happen to think about his mistakes or faults. If something that is not of goodness flashed through your mind, you have to take it as a good opportunity to discover yourself and change. Then, you can quickly change your heart into a God-pleasing heart that is filled with goodness and love.