At cnn.com there's a report of a study that shows spiritual people are more resilient than non-spiritual people.
"Researchers have found that spiritual people have decreased odds of attempting suicide, and that spiritual fitness has a positive impact on quality of life, on coping and on mental health."
Thus, soldiers who have more God-belief cope with war better.
This doesn't surprise me.
If someone believes there is a God and God loves them and guides them and so on, then such belief will have an effect on how one responds to adversity.
The military's use of this finding is creating controversy, since the more spiritual a person is the better soldier (in general) they will make.