The following comes from John Maxwell's Leadership Wired email newsletter where he states that "passion is the fuel of persistence."
Key Points about Passion
1) A person’s inner fire propels him or her to excel. Put simply, desire determines destiny. As a rule, leaders attain influence proportionate to the size of the blaze burning within them.
2) Passion supplies leaders with an extra edge over the competition. After a championship contest, sports commentators occasionally observe how the winning side “wanted it more.” All else being equal, the more passionate team typically prevails.
3) Passion makes the impossible possible. People are wired so that when their souls ignite, they no longer shrink before the barriers in front of them. That’s what makes a passionate leader particularly effective. He or she conceives of possibilities and opportunities for progress whereas dispassionate persons only see roadblocks and reasons why a vision can’t be achieved.
Application: Take Your Temperature
Consult three people (such as a spouse, mentor, or trusted co-worker) to give you an honest assessment about the level of passion they see you exhibit toward your job. Inquire about the ways in which your passion manifests itself most evidently. If they consider your passion to be low, then do some soul-searching to recapture enthusiasm for your work. Why did you enter your present profession? What once excited you about work that no longer may be a source of inspiration? In light of your answers to these questions, ponder ways to ratchet up your passion.