Only in Mormon's book of military history is the quality of spirituality greater than any other. Who would suppose that the spirit of revelation and prophecy are more important for a military leader than experience, organizational skills, and thoughtful strategy? Yet, the Nephites knew who was the source of their success save it were in their times of wickedness.
Consider the advantage of having a captain like Zoram who could commune with the Lord through the prophet Alma to find out the location of the enemy (Alma 16:5-6). Imagine a chief captain like Moroni who consistently put down internal dissension because he understood that the inner vessel must be cleansed first (Alma 46; 50:33; 51:13-19; 62:1-9). He even received direct revelation from the Lord regarding the propriety of this bloody internal cleansing (Alma 60:33). Add to this the many, many times in which the strategy of the Nephites was inspired by the Spirit of the Lord. Then consider how these great captain-prophets would even call the people to repentance if needed (Mormon 3:2-3). In view of the many Nephite victories claimed against incredible odds, it is apparent that their custom of appointing spiritual chief captains was a militarily sound one. These great military leaders fought according to Nephi's motto: O Lord, I have trusted in thee, and I will trust in thee forever. I will not put my trust in the arm of flesh; for I know that cursed is he that putteth his trust in the arm of flesh. Yea, cursed is he that putteth his trust in man or maketh flesh his arm (2 Nephi 4:34).