Alma did not explicitly say what Corianton was upset about in this regard, but it appears that Corianton was preoccupied with some of the fundamental truth-claims of the Gospel. How could he know that Christ would come so long before Christ actually came? How could he know that there will be a resurrection? These were common questions in the Book of Mormon before the first coming of Christ. They are still pressing questions as the world awaits the Second Coming.
If people reject the coming of the Savior, or do not believe in resurrection, then a corollary is that sin is not a serious matter. In 2 Nephi, that same point had been raised. Some people believed in the resurrection of the dead, but the issue was contested frequently, even among the Nephites. For example, in Mosiah 26:1, we are told that the rising generation “could not understand the words of king Benjamin, being little children at the time he spake unto his people,” and in Mosiah 26:2, “they did not believe what had been said concerning the resurrection of the dead.” That was the generation that Alma the Younger had been a part of. One of the concerns that Alma the Younger had was that an increasing number did not believe in the resurrection. Likewise, in Alma 30, Korihor did not see how a just God could punish a sinner. Nehor also argued that God would not punish people and that everyone should be saved.
If we look back over the previous chapters in the book of Alma and examine all of Corianton’s problems, the same undercurrents of argument kept arising. We might have thought that Korihor had been put to rest when he was convicted, smitten, and trampled. However, the last place he went to was the city of Antionum. That is where Corianton had served a mission, so maybe he had encountered some of those ideas among the Zoramites. Korihor had been quite successful in the city of Zarahemla; Nehor also had many followers.
These were clearly not new arguments. Alma had heard them before, and he gave us very carefully thought-out answers to each of these questions. Sometimes, he just rebutted them with his testimony; at other times he quoted scripture. When he taught about the resurrection and how the body would be raised to a perfect form, he quoted his missionary companion, Amulek. In Alma 10 and again in Alma 34, Amulek taught the same doctrines. Here in Alma’s teaching of Corianton, these principles were brought together and crystallized.