Below are some quotes from the book Reset by David Murray which highlight the importance of sleep:

The Sermon We Preach in Our Sleep

Few things are as theological as sleep. Show me your sleep pattern and I’ll show you your theology, because we all preach a sermon in and by our sleep. For example, if we pride ourselves on sleeping only five hours a night, we preach the following truths:

• I don’t trust God with my work, my church, or my family. Sure, I believe God is sovereign, but he needs all the help I can give him. If I don’t do the work, who will? Although Christ has promised to build his church, who’s doing the night shift?
• I don’t respect how my Creator has made me. I am strong enough to cope without God’s gift of sufficient daily sleep (Ps. 3:5; 4:8). I refuse to accept my creaturely limitations and bodily needs (Ps. 127:1–2). I see myself more as a machine than a human being.
• I don’t believe that the soul and body are linked. I can neglect my body and my soul will not suffer. I can weaken my body and not weaken my mind, conscience, and will.
• I don’t need to demonstrate my rest in Christ. Although the Bible repeatedly portrays salvation as rest, I’ll let others do the resting. I want people to know how busy, important, and zealous I am. That’s far more important than the daily demonstration of Christ’s salvation in when and how I rest.
• I worship idols. What I do instead of sleep shines a spotlight on my idols, whether it be late-night football, surfing the Internet, ministry success, or promotion. Why sleep when it does nothing to burnish my reputation or advance my glory? What sermon are you preaching in your sleep?"

Physical Consequences

Numerous studies have warned about the long-term results of chronic sleep deprivation (averaging less than six hours a night). Just one week of sleeping fewer than six hours a night results in damaging changes to more than seven hundred genes, coronary narrowing, and signs of brain tissue loss.3 The latter is partly because sleep activates the brain’s garbage disposal system, cleaning out toxins and waste products.4 Chronic sleep deprivation is associated with increased risk of infection, stroke, cancer, high blood pressure, heart disease, and infertility. Sleep loss increases hunger, desire for larger portion sizes, and preference for high-calorie, highcarb foods, with the resulting risk of obesity.5 In short, sleeping is not a useless waste of time, but an essential biological need that prevents infection and helps us maintain healthy body weight."
3. Many of the statistics and quotations for this section come from Sleep Disorders
and Sleep Deprivation: An Unmet Public Health Problem (Washington DC: National
Academies Press, 2006).
4. L. Xie et al., “Sleep drives metabolite clearance from the adult brain,” National
Center for Biotechnology Information, October 18, 2013, http:// www .ncbi .nlm .nih .gov
/pubmed /2413 6 9 70.
5. Christine Gorman, “Why We Sleep,” Scientific American, October 1, 2015, http://
www .scientific american .com /article /sleep-why-we-sleep-video/.