Repentance

Alma 38:8

"And it came to pass that I was three days and three nights in the most bitter pain and anguish of soul; and never, until I did cry out unto the Lord Jesus Christ for mercy, did I receive a remission of my sins. But behold, I did cry unto him and I did find peace to my soul."

Alma was in torment for 3 days and nights because of all the sin he had committed in his life. For three days and nights he thought he was doomed and that there was no turning back. Through Christ, however, he was able to repent and become a better person permanently. He turned away from the sins and devoted his life to the Lord. It was no free repentance though. He had to do his own work. He had to come to Christ and seek His mercy. We can't expect to sin and be ok. We have to repent of these sins in sincerity and then we'll be filled with peace.