Yea, [Moroni] had been strengthening the armies of the Nephites, and erecting small forts, or places of resort; throwing up banks of earth round about to enclose his armies, and also building walls of stone to encircle them about, round about their cities and the borders of their lands; yea, all round about the land…. But behold, how great was their disappointment; for behold, the Nephites had dug up a ridge of earth round about them, which was so high that the Lamanites could not cast their stones and their arrows at them that they might take effect, neither could they come upon them save it was by their place of entrance… Now behold, the Lamanites could not get into their forts of security by any other way save by the entrance, because of the highness of the bank which had been thrown up, and the depth of the ditch which had been dug round about, save it were by the entrance (Alma 48:8; 49:4, 18).