Alma Ch30

An antichrist named Korihor appears and begins to make fun of the gospel by saying there is no God, no fall of man, no penalty for sin, and no Christ. He contends with Alma and challenges God for a sign who strikes him dumb. He admits that he was visited by the devil and taught what to say against the church, so in the end, he is trodden down until dead being forgotten by the devil.
After that big battle the dead were buried and the 16th year began and ended in peace with fasting, mourning, and prayer throughout the people with strict obedience to the commandments of God (v1-4). It was the same until the end of the 17th year when Korihor began to preach against the prophets which he could legally do because there was freedom of religion meaning that no one was punished for not believing in the churches doctrine (v5-9). There were laws that punished murders, robbers, or adultery but none that could punish Korihor for his preaching against Christ's people (v10-12).
He talked straight to the believers and said they were foolish for believing things that weren't facts including the atonement, the coming of Christ, and acting in a way to gain salvation (v13-17). He preached all these things to make the people start to be selfish and lead their hearts away from God which worked in some places, but when he went to the people of Ammon, they tied him up and was brought before someone who might get ride of him which is what happened in Gideon too (v18-21). In Jershon with the people of Ammon he was flat out kicked out, but in Gideon right after that, they asked him why he is doing all of this evil preaching (v22).
Korihor answered with some nonsense about not believing in foolish traditions that are just in place to control the people and give the power to the priests who make up things, like the coming of Christ, to convince people to support them (v23-27). There are a few more things in those verses like trying to free the people from the oppression of the church that uses their sins to convince them they are needing saving and blah blah blah. But the last point he hits on is about there being no God and no punishment for sinning and that it is all made up to restrict the people (v28).
After making these outlandish statements in Gideon, the people just sent him away to stand before Alma and the other leaders of the church to be dealt with by the head of the church (v29). As he stands before the council of the church he starts accusing them of living off the people of the church, which is ridiculous because Alma has served the people and labored without being paid, in fact, the only time he was paid in the last 17 years is when his job was the first chief judge (v30-33). There is obviously no truth in Korihor's accusing but he stills believes it because he doesn't believe in God or Christ (v34-38).
Alma bears his strong testimony to try and convince Korihor that Christ will come because Korihor has no evidence that Christ will not come except his word, and he already has lied so that's not very convincing (v39-40). Alma has a strong testimony that the teachings of the church is true because he has been converted by an angel, so he knows that Korihor is possessed by the lying spirit of the devil that is trying to work mischief (v40-42). Korihor says that the only way he will say that he believes in God is if there is a sign given, even though there has been plenty of signs given by the holy prophets and even everything on the earth proves there is a God (v43-45).
There is only sadness from Alma towards Korihor for his stubbornness because he knows his soul will be lost than allowed to live on and lead astray the people (v46-47). Korihor is set in his ways and ends up struck dumb from that moment on and then all of a sudden he admits he actually knew there was a God all along but the devil had 'deceived' him and it wasn't really his fault...yeah right (v48-53). He wasn't really penitent though and when he asks for the curse to be lifted that bit of mercy is withheld because he did not have a change of heart, just a change of action for the moment (v54-55).
He was left to beg for food while the truth of all that had happened was proclaimed throughout all of the land to reclaim the hearts that had been lead away (v56-58). Korihor left the Nephites and went among the Zoramites to beg but was run down and killed, and thus we see how those who follow the devil are not supported in the last day (v59-60). As soon as the devil thinks you aren't useful, you will be cast aside and dragged to hell forever.