The Army has released a spiritual fitness guide that encourages soldiers to build inner strength for war and life.

“This guide symbolizes 250 years of the Chaplain Corps standing shoulder to shoulder with you in formations, reaching wherever our soldiers and families are to strengthen the heart, spirit and soul that defends the greatest nation on Earth,” Army Chief of Chaplains Maj. Gen. William Green Jr. wrote in the guide. “Our Army leaders, especially in teams and squads, must be equipped to lead soldiers to success in war and life.”

The guide covers spiritual fitness principles and stages of development and training over nine chapters. It defines spiritual fitness as “the conditioning of a soldier’s spirit towards readiness—to fight and win in war and life.”

Though the guide focuses on spirituality, it is not written with any particular religion or belief system to cater to all soldiers and leaders throughout the service. About 70% of active-duty troops are Christian, 2% are atheist or agnostic, 1% practice “an Eastern religion,” 0.4% are Jewish, 0.4% are Muslim and 24% of troops were “other, unclassified or unknown,” according to a 2019 congressional report.

Soldiers who have a strong belief system, whether in a religion or in values, can lean into their beliefs to persevere “through challenging situations and [reinforce] their commitment to their mission,” according to the guide. For example, soldiers who believe in concepts like duty, honor and sacrifice “can instill a sense of pride and belonging within a unit” and motivate soldiers “to face adversity with unwavering determination.”

Across the Army’s formations, leaders are “essential” and provide “foundational life knowledge and support” to their soldiers, according to the guide. “Leaders embody the role of teacher. … By fostering an environment of open dialogue, leaders can encourage soldiers to explore their shortcomings without fear of judgment,” according to the guide. “Teachers provide educational resources about spiritual fitness and reference developmental practitioners like chaplains or religious affairs specialists to help soldiers understand the importance of their spiritual fitness growth.”

Spiritual resources enable soldiers to “thrive in demanding environments and navigate life’s complexities with resolve,” Army Chaplain Corps Regimental Sgt. Maj. Meaghan Simmons wrote in the guide.

“In our challenging world, spiritual fitness is essential for resilience, adaptability, and mission readiness,” she wrote. “When soldiers derive purpose from their source of inner strength and collective mission, they become unstoppable in war.”

Read the full guide here.