Alma continues, providing important context to support this interpretation of Corianton’s apostasy. He has named the two worst sins (denying the Holy Ghost and committing murder); now he explains why they are the worst. The first is unpardonable, and the second one is very difficult to obtain forgiveness for. By implication, the third worst sin would be one from which the sinner refuses to repent. Apostasy fits that definition.
Alma is contrasting the unpardonable and the unforgivable against the pardonable and forgivable. “Persons guilty of unchastity may receive forgiveness through full repentance.” “Serious as is the sin of fornication, there is forgiveness upon condition of total repentance.” Consorting with a harlot is forgivable upon complete and sincere repentance. Yet how could someone in a state of apostasy from the God who could forgive exercise faith to repent?
The “sin next to murder” is not appropriately applied to forgivable sexual transgressions but to that sin that causes others to lose their faith and therefore their salvation (and desire/ability to repent). Jorgensen declares:
Here, I suggest, we do approach a form of sin, a burden that will be upon Corianton’s soul because he was called to the ministry, that we can take seriously as next to murder, near to the shedding of innocent blood: Corianton’s bad conduct, forsaking the ministry and running off to the borders, has made him like the harlot and like the devil, one who “lead(s) away the hearts of many people to destruction.” Spiritually this is near to murder, for murder takes away the life of the body and cuts short the “space for repentance” (Alma 42:5) that God grants to every soul in the world, and this leading by bad conduct does delay and may prevent the repentance of those whose hearts are led away: “they would not believe in my words.”