Book of Alma Chapter Twenty. Book of Mormon 1830 First Edition.

A large battle ensues, the lamanites along with the Zoramites and Amalekites go to attack the Nephites in the land of Zarahemla. Moroni is their chief and prepares the people to defend their families and their freedom and their land and their faith. They have helmets, breast plates and arm shields. Alma is asked to pray and discover which way the armies of the Lamanites have gone after they retreat from around the land of Jershon. Alma is told they are returning to attack via the land of Manti. Moroni uses strategy to protect his people and hides his armies to surround the Lamanites. The Lamanites are naked except for loin clothes, but have all weapons like the Nephites. Many are killed. Moroni asks for the Lamanites to make a covenant to stop their attacks and to hand over their weapon. Their chief says they will hand over their weapons but not enter a covenant and so the battle continued until the lamanites saw they were defeated and gave their weapons up and made a covenant. The dead bodies went into the river Sidon, they were un-numbered as there were so many.