In Alma 55, Moroni has a desire to free the Nephites who are held prisoner by the Lamanites in the city of Gid. The challenge he faces is that Gid is well fortified, with a wall surrounding the city and Lamanite guards keeping watch over the entrance to the city.
But Moroni has a plan. The guards are given strong wine, and they become drunk and fall into a deep sleep. The Nephites then toss weapons over the wall of the city, which are then distributed to the Nephite prisoners. Weapons are given to everyone, "even to their women, and all of their children, as many as were able to use a weapon of war" (verse 17).
When the Lamanites awaken the next morning, they have no choice but to surrender, as all the Nephites — the prisoners inside the walls of the city and the Nephite army outside the city — are now armed and ready for battle. Arming everyone for the battle is the only strategy that could have worked. The Nephite army did not have the same access to the Lamanites that those "on the inside" did, so everyone's participation was needed to win this battle.