As stated before, Aaron’s “reading the scriptures” is evidence that copies of the contents of the plates of brass had been made probably for easier access. Ammon had read from the same text in the land of Ishmael during the same time period (v. 12; see Alma 18:36). As Aaron expounds the scriptures to the father of King Lamoni, he bears testimony of the same principles of the gospel that Ammon had borne to Lamoni: the creation, the fall, the plan of redemption, the atonement, and the resurrection (Alma 22:13–14).
Apparently the Spirit bore witness of the truthfulness of Aaron’s words to the head king. He recognized his own unworthiness and need for repentance and rebirth (v. 15). There is a major difference between his having listened to Aaron and his previous encounter with Ammon. With Ammon, because of fear, the king had offered one-half of his kingdom for his life (see Alma 20:23). With Aaron, because of his desire for eternal life, he offered to give up all and forsake all (Alma 22:15). In response to the king’s offer, Aaron outlines the process to begin the path towards eternal life (v. 16).
An agnostic, one who doesn’t really know if there is a God, will usually refuse to pray to God because he or she feels it would be hypocritical to pray to someone in whom there is no belief. Again, the Book of Mormon gives us an answer to such a feeling. The prayer offered by the head king is not in the least hypocritical. He addresses God “if there is a God” and asks if he whom he addresses is God. Then he adds one more dimension. He already had committed to give up his worldly possessions and position, now he offers to give up all his sins (v. 18). Giving up one’s sin is the essential requirement for receiving the blessings of salvation in the kingdom of God. The latter commitment brought about his being struck as if he were dead (v. 18). The Spirit was undertaking the cleansing of unbelief and darkness of his soul, as his son, his son’s wife, and servants had experienced through the testimony of Ammon (see Alma 18:42–19:34).