The fingers of my left hand strained to reach their places on the fretboard, and as my right hand swept the pick across the strings, I overshot and struck the next set too. “Ping, thunk. Ping, thunk.” It sounded like someone had stepped on a cat’s tail and then grabbed it by the windpipe.

Frustration knotted in my chest and I sat back from my mandolin with a huff. In a deja vu moment I saw myself as a beginner piano student pressing my uncontrollable fingers hard against the keys, the dissonant sound echoing what I felt inside. That was before I discovered the secret weapon I didn’t know I had.

What you’re not always told when you begin play an instrument is that your body possesses a type of memory that records repeated movements and etches them into your brain, so in time you will be able to do without conscious effort what is now awkward and uncomfortable. After I discovered muscle memory and learned how to use it, my frustration level dropped, since I knew my practice was sure to pay off.

The remembrance of this truth renewed my determination to persevere. Shoving down my impatience, I resumed practice, carefully picking the notes. The choked cat yowls didn’t disappear, but they did become less frequent.

We will face challenges and be tempted to quit whenever we set out to achieve something. But if we want to reach our goal, we must finish what we start. This is the most basic requirement for any reward, because nothing is useful unless it is completed. This is true, not only in the projects we undertake, but also in our faith. Just like we intend to finish the projects we begin so they may be useful, so God intends to bring our faith to maturity so we may be useful. He does this by testing our faith, and though being tested is not always fun, gaining maturity in faith is always beneficial in every area of life.

Regardless of the goal we are trying to reach, there is one necessity for completion: endurance. If you’re like me, trying to persevere just because you know you should doesn’t work out that well. You need something more to turn you from a sprinter into a marathoner. That something is faith – confidence in your reward. When I apply the knowledge of muscle memory as I practice an instrument, I am able to endure the times when practice is difficult, because I know that with enough repetition, my fingers will automatically reach for the right notes. Likewise, when we apply the knowledge of God’s trustworthiness to our lives, we can endure challenges because God promises to reward our endurance and He has the power to keep His promises.

Faith and muscle memory are like trains that will carry you to your goal, even through the dark tunnels of struggle and opposition. It takes endurance to stay on the train, especially when it feels like you’re hanging on for dear life on top of it instead of riding safely inside. But if you want to see the light at the end of the tunnel, you can’t jump off the train in the dark. It is by putting your hope in the right place – the sure and firm character of God – and choosing to believe Him in all He says that you will gain the strength to stay on the train until you reach your reward.

By faith you endure to receive the reward, and because of your faith you will be rewarded.

So be confident, and endure. Your reward will come.