Answer:
The Mormon battalion was formed to serve the American Army in the Mexican-American War in exchange for aid to the destitute of Nauvoo.
Step-by-step explanation:
While the Saints were in Iowa, Captain James Allen of the United States Army sought Brigham Young, who was the president of the Church of Jesus Christ of Latter-day Saints. Captain Allen reported that the president of the United States wanted 500 men from the Church to join the army to help in the war against Mexico.
During the Mexican-American War, the United States Army captain contacted the leader of the Church of Jesus Christ of Latter-day Saints, urging men to fight in the war. Although church members were going through a difficult time, their leader persuaded them to form an army to help the American army because this would show that the church supported the union and the salary they would receive would be used to help the needy. In this way, the Mormon battalion was born.