Christ is "the author and finisher of our faith." Footnote re: finisher tells us that it represents an idea in Greek close to "one who perfects, completes."
I was just reading in Preach My Gospel about how Jesus Christ finished his mission on earth (see John 17:4, John 19:30). Just another way in which I desperately want to be more like Him. It is often so difficult to finish things I start (take this blog, for example!). But He is my perfect example. Not only can I draw strength from His example, I can rely on His Atonement for strength to do things that are beyond my natural capacity.