Lehi was the younger of the two sons of Helaman, chief judge over the Nephites, named after the elder Lehi who left Jerusalem; his brother Nephi was the elder (Helaman 3:21). His father gave him the name so that he would remember the works of his first parents, charging him that salvation comes only through the atoning blood of Jesus Christ and that he must build on the rock of the Redeemer so that no storm could drag him down (Helaman 5:6, 9, 12). He was “not a whit behind” Nephi in righteousness, and the two preached together, having “many revelations daily” (Helaman 11:19, 23).
Around 30 B.C., after Nephi gave up the judgment-seat to preach for the rest of his days, Lehi joined him in the ministry (Helaman 5:4). Their preaching baptized eight thousand Lamanites in and around the land of Zarahemla (Helaman 5:19). They then went to the land of Nephi, where they were imprisoned and, after many days without food, were about to be killed. They were encircled by a pillar of fire that did not burn them, and the Lamanites dared not lay hands on them for fear of being burned (Helaman 5:22-24).
In the prison their faces shone “even as the faces of angels” as they looked to heaven, and angels came down and ministered to them (Helaman 5:36, 48). About three hundred people saw and heard these things (Helaman 5:49) and then went out to declare them, convincing most of the Lamanites (Helaman 5:50). Moroni later wrote that it was the faith of Nephi and Lehi that changed the Lamanites, who were baptized with fire and with the Holy Ghost (Ether 12:14). In the sixty-third year Lehi and Nephi went into the land northward to preach (Helaman 6:6).