When they were released from prison in Middoni, in spite of what they had suffered, Aaron and those who were with him continued their mission and were led by the Spirit to the land of Nephi where Lamoni's father, the king over all the Lamanites, lived. They had the opportunity to teach the king. They taught from the scriptures.
13 And Aaron did expound unto him the scriptures from the creation of Adam, laying the fall of man before him, and their carnal state and also the plan of redemption, which was prepared from the foundation of the world, through Christ, for all whosoever would believe on his name
The Holy Scriptures are powerful tools to teach and testify of the plan of redemption. If we want to help others know the truth about the plan of salvation and the role of Jesus Christ, we have to open the scriptures to their understanding. They teach this simple truth:
14 . . . since man had fallen he could not merit anything of himself; but the sufferings and death of Christ atone for their sins, through faith and repentance, . . . ; and that he breaketh the bands of death, that the grave shall have no victory, and that the sting of death should be swallowed up in the hopes of glory
The king's great desire to know these things for himself and to feel the promised joy and peace led to the following remarkable prayer:
18 O God, Aaron hath told me that there is a God; and if there is a God, and if thou art God, wilt thou make thyself known unto me, and I will give away all my sins to know thee, and that I may be raised from the dead, and be saved at the last day.
You can't hold on to your sins and know God. We sometimes say to ourselves, "I will love God, but I can't quit doing this or that." The king was willing to submit to the Lord and forsake all of his sins in order to know God.