Less than three weeks ago, I watched as my husband, Nathan, became the commanding officer of a U.S. Marine Corps infantry company. About 160 men, most of them barely adults, stood at attention in their camouflage and combat boots and waited as he became their leader. Moments earlier, some of the troops had curbed their cursing and offered startled greetings—"Afternoon, Ma'am"—when they saw me standing there in my dress and heels. It was a Friday.

The following Tuesday, I watched via televised address as my President announced a plan to dramatically decrease the number of troops in Afghanistan. The network-worthy news that evening was that we will be reducing our forces from the current 100,000 to about 67,000 by next summer. That's a quick decrease of nearly a third—"a drawdown," President Obama called it, which in many ways sounded altogether promising.

War-weary like everybody is, as a military wife I have perhaps more reasons to be overjoyed at prospects: Another war over! We're getting out of there, finally! But my response to the announcement was instead lit by the light of the week before, by my husband and 160 other living, breathing men lined up in a dusty military gym. By how much he means to me and by my fears of what could happen to any one of them. In many respects, the concerns I have are not unfounded; in fact, I justify them by the fact that they are bona fide news stories.

For instance, it was reported only months ago that the number of troops killed by IEDs (Improvised Explosive Devices—roadside bombs) in Afghanistan rose by 60 percent last year, while the number of troops wounded by them tripled. Ask any 19-year-old deploying to Afghanistan, and he's not worried about the Taliban so much as he's worried about some guy who took a lucrative job rigging trip wire and fertilizer, blowing up U.S. convoys.

And recent military operations in Afghanistan seem to suggest that the presence of troops brings stability to a region. Last year, Marines settled into the Sangin province of Afghanistan and began patroling aggressively to root out drug lords and Taliban militants. At first, the fighting was so fierce that Sangin became known as the "Fallujah of Afghanistan," but in time and at great expense, the Marines battled until the majority of insurgents had left. The region began to experience something like peace and even had a visit from Defense Secretary Robert Gates, who noted the "dramatic turnaround" brought by the Marines' presence.

In Iraq, where another drawdown and another U.S. mission are yet to be complete, last month was the bloodiest since 2008 for U.S. forces in the country. It could be argued, then, that when large numbers of troops leave, for a time things become far more dangerous for those who remain.

I'm afraid that when Nathan's company leaves for Afghanistan on schedule next year, the decrease in troop numbers will mean a higher likelihood of ambush or attack. I'm afraid that because the ratio of troops to terrorists will be significantly smaller, there will be significantly more chances that the man I love could be shot, captured, tortured, you name it. I'm afraid that fewer U.S. troops will mean larger areas for those troops to cover, which will mean travel, which will mean IEDs. And I'm afraid of all the typical 21st century combat risks, like sniper fire and traumatic brain injuries and PTSD.

And yet: "Fear not." The Bible says it over and over: "Don't be afraid." "Do not fear." "Fear not." Even a minimal amount of time spent in churches will teach you that this is the most often-made commandment in all of Scripture. But why?

The thing about fear is that it does not ultimately trust. This is why it feels insecure entirely, why it can grip so wholly. Fear refuses to believe that even the terrible and horrific events of this life can be used for God's glory, for ultimate good. It denies that our individual health and wealth, that all our lives and all our hopes are subject to God's purposes. It rejects the biblical teaching that God is pure love and that therefore what he directs and allows is worth trusting, even when it seems to rip us to shreds.

"Fear not"—this is so much easier read than done, and there is enough mistrust in each of us to make it seem impossible. But God is pure love, and part of his loving work in us is that he gives us increased faith: an ability to trust him and believe, an assurance of the things we can't seem to see.

Does God expect that we will never be afraid? The Bible doesn't say that. It's safe to assume that as long as humanity has a sin condition, not a single person will ever be fear-free. But in the midst of whatever keeps us up late at night, whatever has us most worried and petrified, we can be certain of the Voice that repeatedly commands comfort amid our unbelief. Fear not: He is holding everything well, come what may.

Lisa Velthouse is the author of 'Craving Grace: A Story of Faith, Failure, and My Search for Sweetness, a memoir (Tyndale House.) She blogs regularly at LisaVelthouse.com, and can also be found on her Facebook page and Twitter feed. She has written for Her.meneutics about lying memoirs'.