If a man remains in me and I in him, he will bear much fruit. (John 15:5)

I USED TO BE A RUNNER. Starting in elementary school, running was what I loved most—especially the grueling long-distance races that took perseverance more than speed. As a young adult, I participated in triathlons and trained for half-marathons. While I was in top shape, running wasn’t painful or daunting; it was even rather enjoyable.

I never decided to quit running. I just got preoccupied, and the activity slipped from my daily life. Now, as I consider how to get back into shape, I wish I had stuck with it. Even a 5K sounds intimidating to me now.

It’s so much harder to get back in shape than to stay that way, isn’t it? This is a principle Jesus tried to drive home when He told His followers to “remain” in Him. He used the analogy of gardening instead of running, but the concept is the same. Whether it’s conditioning for a race or pruning branches to bear fruit, reaching optimum form is hard work. Why let it slip away? “You are already clean because of the word I have spoken to you,” Jesus said (see John 15:3). “Remain in me.”

If Christ has brought you to a place of spiritual maturity, don’t waste it. When you’re connected to Christ, you are walking in the light—and there is no better place to be. Hold on to this gift with perseverance and diligence.

Choose a spiritual discipline to engage on a daily basis.

Heather Gemmen Wilson is the author of the Global Warning Series (WPH), a fiction series for preteens. She is married to a Wesleyan pastor.