Alma 18:36 - 18:43
Alma 18:36 Now when Ammon had said these words, he began at the creation of the world, and also the creation of Adam, and told him all the things concerning the fall of man, and rehearsed and laid before him the records and the holy scriptures of the people, which had been spoken by the prophets, even down to the time that their father, Lehi, left Jerusalem.
Ammon began to teach Lamoni all the events of history that are written in the scriptures. He started with the creation, Adam and Eve, and the fall. He also told Lamoni about Lehi and his family and their leaving Jerusalem those many years ago.
I am going to assume that Ammon had a copy of their scriptures with him. It probably had a copy of, at least, part of the material in the brass plates that Lehi brought with him.
Alma 18:37 And he also rehearsed unto them (for it was unto the king and to his servants) all the journeyings of their fathers in the wilderness, and all their sufferings with hunger and thirst, and their travail, and so forth.
Ammon also went over the events in the life of Lehi while he was traveling from Jerusalem to the promised land. He went into detail as their difficulties such as hunger, thirst and conflicts between themselves and probably not so friendly people in the areas they traveled through.
Alma 18:38 And he also rehearsed unto them concerning the rebellions of Laman and Lemuel, and the sons of Ishmael, yea, all their rebellions did he relate unto them; and he expounded unto them all the records and scriptures from the time that Lehi left Jerusalem down to the present time.
In addition, Ammon described the rebellion of Laman and Lemuel along with the sons of Ishmael while they were traveling in the desert towards the land of Promise. He also discussed the history of the Nephites and Lamanites up to their own day.
Alma 18:39 But this is not all; for he expounded unto them the plan of redemption, which was prepared from the foundation of the world; and he also made known unto them concerning the coming of Christ, and all the works of the Lord did he make known unto them.
Ammon also talked in detail about the plan of redemption, the mission of the Savior in mortality and that all this was planned from before the world was created.
Alma 18:40 And it came to pass that after he had said all these things, and expounded them to the king, that the king believed all his words.
Lamoni believed all that Ammon had told him.
Alma 18:41 And he began to cry unto the Lord, saying: O Lord, have mercy; according to thy abundant mercy which thou hast had upon the people of Nephi, have upon me, and my people.
Lamoni was very struck with what Ammon had told him. He could see that the Nephites had been blessed as they tried to be faithful to the gospel. Lamoni could now see what the problem was among his own people and wanted that same spirit that the Nephites enjoyed to be among his people so they could be blessed in like manner. He therefore began a verbal prayer to God to try to connect with God for his own behave and that of his people.
Alma 18:42 And now, when he had said this, he fell unto the earth, as if he were dead.
As he began his prayer, he was so overcome that he fainted and collapsed.
Alma 18:43 And it came to pass that his servants took him and carried him in unto his wife, and laid him upon a bed; and he lay as if he were dead for the space of two days and two nights; and his wife, and his sons, and his daughters mourned over him, after the manner of the Lamanites, greatly lamenting his loss.
The king’s servants thinking he might be dead, took his body to the queen and laid him on their bed. For two days, he lay there and it appeared as if he were dead. Lamoni’s family had even started the traditional rituals for the dead that was normal among the Lamanites.