Part of growing and staying healthy is exercise. When we exercise our bodies grow stronger. However a lack of exercise not only hinders growth but causes our bodies to grow the wrong way (sideways). This degrades performance and could also lead to unattractiveness of the physical body (subjective to the viewer). God designed our body a specific way, and by exercising we allow our bodies to achieve its full potential.
You’ve been raised on the Message of the faith and have followed sound teaching. Now pass on this counsel to the followers of Jesus there, and you’ll be a good servant of Jesus. Stay clear of silly stories that get dressed up as religion. Exercise daily in God—no spiritual flabbiness, please! Workouts in the gymnasium are useful, but a disciplined life in God is far more so, making you fit both today and forever. – 1 Tim 4:6-8 (MSG)
Likewise a Christian needs to excercise to build their spiritual life, this excercise means to use what we have learnt from God. Using what we have learnt to bless others, to serve and to glorify God. Without spiritual exercise, our spiritual life becomes flabby and weak. What can you do today to perform spiritual exercise?