When Ammoron’s army saw the arrival of the new battalion of young men, they retreated and delayed their attack on Judea, allowing time for the Nephites to work on reinforcement. “And thus were we favored of the Lord; for had they come upon us in this our weakness they might have perhaps destroyed our little army; but thus were we preserved” (v. 19).
Helaman and his young warriors moved out as bait appearing to go to a neighboring city (v. 30); the Lamanites pursued them; Antipus, the Nephite commander, and his army chased the Lamanite army. Eventually Helaman turned back, not knowing what had happened to Antipus, and arrived at the battle just in time with his 2,000 brave warriors to allow the weak and worn out Nephites to regroup and surround and conquer the Lamanites. Although Antipus had been killed, not one of Helaman’s sons had fallen. The city was spared on the third day of the seventh month (v.42). The seventh month of the year was Passover month. This event occurred on the third day of the seventh month about 66 B.C., and Passover was celebrated on the fourteenth [in the evening] and fifteenth days. As it were, the destroying angel passed over these young soldiers on this occasion. They had great courage (v. 45), did not fear death, and fought for the liberty of their fathers having been taught by their mothers “that if they did not doubt, God would deliver them” (v. 47).
Book of Mormon Central, How Realistic are Nephite Battle Strategies? (Alma 56:30),” KnoWhy 164 (August 12, 2016). “These seemingly sudden, illogical actions … speak volumes about the authenticity of the text and the military expertise of the author, as when all of the clues provided in the text are examined in depth, the logic becomes apparent” (David E. Spencer, Captain Moroni’s Command: Dynamics of Warfare in the Book of Mormon (Springville, UT: Cedar Fort, 2015)).