Hugh Nibley
"Moroni's defenses were based on a series of strong points, being a defense in depth, as modern defense-lines are; beside specially placed 'small forts, or places of resort,' towns and cities on the line were also converted into strong points (Alma 48:8). Such an arrangement can take the momentum out of any military steamroller and slow down or stop any attacking force, no matter how formidable, by forcing it to reduce one strong place after another or else bypass the fortifications and thereby leave dangerous enemy forces in its rear to disrupt communications and launch harassing counter-attacks on invading units. With this strictly defensive program (the preparation being to fight if at all only on their own grounds), an early-warning system was all-important. And it was Moroni's idea that God himself would provide such a system if the people were only faithful: 'If they were faithful in keeping the commandments of God that he would . . . warn them to flee, or to prepare for war, according to their danger; and also, that God would make it known unto them whither they should go to defend themselves' (Alma 48:15-16). In short, God was their 'Dew-line,' their radar, and warning system, and that saved them the need of constant and costly vigilance on all fronts, to say nothing of expensive and wasteful war-plans and war-games. This was Moroni's policy of preparedness, 'this was the faith of Moroni and his heart did glory in it; not in the shedding of blood but in doing good' (Alma 48:16)." (Since Cumorah, p. 307)