By Michael Kelley

The olm (Proteus anguinus) is a species of blind amphibians endemic to the the deep underground caves of the Dinaric karst of southeastern Europe. The unusual appearance of the olm is the result of extensive adaptations to its habitat. Olms inhabit deep underground lakes and pools, where they spend their entire lives in almost complete darkness. As a result, the skin of these animals is devoid of pigment, making it resemble human flesh. The local name of the creature is "oveja Ribica," which means "Human Fish" because of its fleshy coloration. The olm can live for more than 100 years and survive 14 years without food.

The eyes of the olm are severely underdeveloped, an adaptation to its dark surroundings. Larval olms retain normal eyes for the first four months of life before the organs start to regress. By the time the species reaches its adult stage, the visual system has almost completely atrophied.

Did you catch that? They are born with normal eyes; then, because they live their entire lives in complete darkness, their entire visual system atrophies. It is rendered obsolete through disuse.

In other words, use it or lose it.

And that principle - the principle of using something or losing it - is not just applicable here - it's applicable in a lot of other areas of life. We call these things perishable skills because they have to be used and maintained or they will deteriorate and become obsolete eventually. Driving, for example, is a perishable skill. So are a lot of programming languages and other kinds of technical capabilities.

The principle even transfers over to our spiritual lives.

Use it or lose it, Christian. Don't let your spiritual sense atrophy. As a child of light, don't spend your life dwelling in the darkness. Pray, read the Scriptures, meditate on the promises of God, worship with the saints. Exercise your spiritual senses, lest they begin to atrophy:

"Therefore, I say this and testify in the Lord: You should no longer walk as the Gentiles walk, in the futility of their thoughts. They are darkened in their understanding excluded from the life of God, because of the ignorance that is in them and because of the hardness of their hearts. They became callous and gave themselves over to promiscuity for the practice of every kind of impurity with a desire for more and more. But that is not how you learned about the Messiah, assuming you heard about Him and were taught by Him, because the truth is in Jesus. You took off your former way of life, the old self that is corrupted by deceitful desires; you are being renewed in the spirit of your minds; you put on the new self, the one created according to God's likeness in righteousness and purity of the truth" (Ephesians 4:17-24).

Do you see the progression in this passage? It's not unlike the olm. When we are born again, we are given new sight. In fact, all our spiritual senses are awakened to see, take in, and feel things in a brand new way - a way that is defined by the gospel. But having been given that new set of senses, we must also walk in a new way. We have to use these spiritual senses, or we will lose them.

As children of light, we cannot live like children of darkness. If we choose to do so, then it's just a matter of time until those new senses will atrophy. We will, eventually, become accustomed to living in the darkness because we haven't exercised our eyes. That means that not only must we take off our former way of life; we must continue to take it off and put on a new way of life in its place.

Let's be careful, Christians - let's be careful to not live in caves so long that we can no longer see the light. Exercise the new senses given to you. Don't let them atrophy due to disuse. Today is the day.

Michael Kelley is a husband, father of three, author, and speaker from Nashville, TN. His latest book is a year-long family devotional guide called The Whole Story for the Whole Family. Find his personal blog at michaelkelley.co.