Section 4 of Benjamin’s speech (3:11–27) discusses the doctrinal theology and the religious behaviors that are consistent with repentance and the transformation that comes with the Atonement.
In Section 2 of his speech, Benjamin made it clear that people must repent of their own sins and not remain and die an enemy to God (see, for example, 2:38). This will allow the Atonement to make it possible for people to "dwell with God in a state of never-ending happiness" (2:41). As he turns to the legal, religious, and practical operations of the atoning blood of Christ, Benjamin now conveys additional important information that certain transgressions or human conditions will be automatically covered by the "infinite and eternal" Atonement, as Amulek will later call it (Alma 34:15). King Benjamin first tells his people that the Atonement is guaranteed to cover three things:
Christ’s atoning blood covers the direct effects of the Fall. As Lehi declared, "the Messiah cometh in the fullness of time, that he may redeem the children of men from the fall" (2 Nephi 2:26–27). Similarly, the Apostle Paul was aware of this doctrine and taught, "For as in Adam all die, even so in Christ shall all be made alive" (1 Corinthians. 15:22). The New Testament talks about Jesus as the second Adam because Christ counters the effects of the first Adam. King Benjamin understood this too. Thus, we believe that we will be punished for our own sins and not for Adam’s transgressions (Article of Faith 2).
Many people who have lived, have not known the general will of God concerning them. They did not know the plan of God, the plan of redemption, or the plan of mercy, and how to obtain these blessings. They have done things that were wrong and they felt were wrong, but they died not knowing what they should do to reconcile with God concerning that matter. The Atonement will cover all of that as well.
This third type of sin is somewhat different from the second in Benjamin’s list. This category refers to specific things that people have consciously done but were unaware that what they were doing was actually against some point of the law, or involved some particular impurities that they may have come in contact with, not knowing that they had inadvertently contravened a law that they knew full well. The phrase "ignorantly sin" probably seems strange to modern Christian readers. Isn’t sin coming out in open rebellion against God, consciously going against His will. Yes, but while that is generally the case, in fact, it is also quite possible to do something deliberately while being mistaken or completely unaware that doing so actually contravenes a law of God or has unintended consequences that are damaging or have the effects of distancing us from God or other people whom we should love.
In Numbers 15:27–29, the Law of Moses actually makes provisions for covering such "ignorant sins." For instance, someone could unconsciously or accidentally contract impurity or do something while not aware that it was in violation of the Law of Moses. If so, it was considered to be an "ignorant sin." How would such a sin be taken care of? Perhaps the person was completely unaware that it had even happened. How would then one repent of it, or know to go to the temple and make a sacrifice for it? Actually, that was one of the things that was covered under the Law of Moses on the Day of Atonement. The High Priest’s sacrifice on the Day of Atonement would cover all of the sins and transgressions that had been committed ignorantly.
We don’t think about such accidental matters as sins any longer, but in Benjamin’s day they did. Maybe we should be grateful to Jesus Christ for having taken care of all such things, so that we need not be troubled or afraid on this account.