"In war, moral power is to physical as three parts out of four." -- Attributed to Napoleon by Maturin M. Ballou, Treasury of Thought, p. 407 (1899).
It is said that Naploeon read an early French translation of Sun Tzu's Art of War, although I doubt he was entirely conversant with the complexities of that Chinese general's discussions of the importance of ch'i, sometimes rendered as troop morale, or moral force.
Paging through Ralph D. Sawyer's translation and historical introduction of Art of War about 2 in the morning, I came across the quote below in one of the footnotes, which bears remembering, especially if you are committed Christian fighting for a principle that you don't mind dying for.
The concept and manipulation of ch'i have already been briefly discussed in the introduction. They are fundamental topics in the military writings; each thinker proposes different methods for attaining courage, for developing the ch'i necessary in the soldiers. A separate monograph on the psychology of ch'i in battlefield contexts would be required to fully address the subject, which might well be summarized by a passage from the Wei Liao-tzu: "Now the means by which the general fights is the people; the means by which the people fight is their ch'i. When their ch'i is substantial they will fight; when their ch'i has been snatched away they will run off." (Combat Awesomeness," p. 247). The ideal was to nurture warriors oblivious to death, who would therefore fight with invincibility and awesome power. The image of a warrior committed to death is found in several writings, sometimes placed in . . . the Wu-tzu -- in the woods. Wu Ch'i said: "Now if there is a murderous villain hidden in the woods, even though one thousand men pursue him they all look around like owls and glance about like wolves. Why? They are afraid that violence will erupt and harm them personally. Thus one man oblivious to life and death can frighten one thousand."