After King Noah's "reduced" army returned from their search for Alma and his followers, there arose a division among the people. The majority of the people did not oppose the king, however "the lesser part began to breathe out threatenings against the king." (Mosiah 19:2-3).
The leader of this lesser part was a man named Gideon. He was a strong man and he "swore in his wrath that he would slay the king." (Mosiah 19:4)
Gideon played a significant role in the Nephite history. He led the upraising against King Noah and almost slays him on one of the king's towers. But he spared the king's life (despite his oath) after the king pleaded with him because of the approaching Lamanite army. (Mosiah 19:6) The king then commanded the people to flee and to leave their families. (Mosiah 19:11) Gideon preferred to stay rather than flee. After they appeased the Lamanites, Gideon sent a secret group of men to search for the king and those who followed him. This group of men found the followers of the king and learned that they had burned the king, but they were not able to capture the priests.
After a couple of years of peace, the Lamanites attacked the people of Limhi because they thought that Limhi's people had taken the 24 Lamanites daughters. (Mosiah 20:1-5) Limhi was about to search his people when Gideon counseled him to not search his people and lay the blame on them, but that he should remember the priests of his father and that they were most likely the ones responsible for the abductions. King Limhi took Gideon's counsel and explained to the captured Lamanite king and the Lamanite king was able to appease the approaching Lamanite army. (Mosiah 20:24-26)
A few years later, after Limhi's people had been under considerable oppression by the hand of the Lamanites, Ammon and his search and rescue party discovered King Limhi. This discovery spurred the evacuation plan. Again, Gideon played a key role by advising the king how best to escape from the Lamanites. His plan proved successful. (Mosiah 22)
And lastly, when Gideon was old and was carrying out his calling as a teacher (Alma 1:7), he courageously stood up to the lying of Nehor. Nehor became "wroth with Gideon" and killed him with a sword. Thus ended the life of a valiant servant of God. We also know that there is a land and valley and a city named after Gideon (Alma 6:7-8).
The Priests of Noah - Amulon
Just as Abinadi and Alma the Elder played a very significant role in the history of the Book of Mormon … a role for good, so do the wicked priests of King Noah and especially Amulon play a very significant role, albeit a role for evil.
Their wickedness did not end with the death of King Noah. I personally think that they had more real power than King Noah. The only evidence I have is found in Mosiah 17:11-12 where the king is about to release Abinadi, but the priests seemingly manipulate the king so as to force him to kill Abinadi. Also, the fact that King Noah is burned to death and the priests escape is suspicious too.
The leader of the wicked priests of King Noah is Amulon. (Mosiah 23:32). We later read how he gains favor in the eyes of the Lamanites and thus gains power over the people of Alma and persecutes them. We can be sure that Alma and Amulon knew each other well.
Amulon left a legacy among the Lamanites. Not only did he take one of the daughters of the Lamanites to wife, but he and the other priests taught the Lamanites the language of Nephi (Mosiah 24:4) and how to keep records and how to correspond one with another (Mosiah 24:6). But he did not teach the Lamanites the word of God.
Many years later we read of the miraculous conversion of many Lamanites by the hand of Ammon and the sons of Mosiah. The one group of Lamanites that did not convert were the descendents of Amulon. It was by the hand of these descendants that many of the Ammonites (or Anti-Nephi-Lehis) were killed. (Alma 24:2). Later on, the true Lamanites hunt down and kill every descendant of Amulon. (Alma 25:7-8)
Alma 24:29-30 appropriately notes, "Now, among those who joined the people of the Lord, there were none who were Amalekites or Amulonites, or who were of the order of Nehor, but they were actual descendants of Laman and Lemuel.
"And thus we can plainly discern, that after a people have been once enlightened by the Spirit of God, and have had great knowledge of things pertaining to righteousness, and then have fallen away into sin and transgression, they become more hardened, and thus their state becomes worse than though they had never known these things."
And so we can plainly see the fruits of Abinadi and Alma and the fruits of King Noah and Amulon; the former two fulfilling their duties and having a tremendous positive effect on the people while the later two were the cause of much contention, corruption and bloodshed.