I've been reading Tad R. Callister's The Infinite Atonement and it has been not only enlightening but beautifully complimentary to my recent study and reflection. For example,
I'd never noticed that there are actually TWO spiritual deaths referred to in the scriptures. Samuel the Lamanite teaches the difference between the two in the Book of Mormon when he explains that the Savior's death "bringeth to pass the resurrection, and redeemeth all mankind from the first death -- that spiritual death; for all mankind, by the fall of Adam being cut off from the presence of the Lord, are considered as dead" (Helaman 14:16) and that "whosoever repenteth not is hewn down and cast into the fire; and there cometh upon them again a spiritual death, yea, a second death, for they are cut off again as to thing pertaining to righteousness" (Helaman 14:18).
Callister explains that understanding that there are these two spiritual deaths, in addition to physical death, is critical in understanding how the Atonement overcomes these deaths, i.e. what the Atonement accomplishes.
I knew that the Atonement unconditionally overcomes physical death for all men, that all will have their physical bodies resurrected, "as in Adam all die, even so in Christ shall all be made alive" (1 Corin. 15:22) but I did not realize that this verse from Corinthians applies beyond that...that it refers to spiritual death as well!
"There is a prevailing idea that although the resurrection is free, only those who repent and obey the gospel will ever return to the presence of God. Those who adhere to this idea, however, seem to have missed a very essential point and fundamental concept of the Atonement, and that is that Jesus Christ has redeemed all minkind from all the consequences of the fall of Adam.
The scriptures teach that every person, saint or sinner, will return to the presence of God after the resurrection. It may be only a temporary reunion in his presence, but justice requires that all that was lost in Adam be restored in Jesus Christ. Every person will return to God's presence, behold his face, and be judged for his own works. Then, those who have obeyed the gospel will be able to stay in his presence, while all others will have to be shut out of his presence a second time and will thus die what is called a second spiritual death." (Robert J. Mathews --- A Bible!)
So like Samuel taught, ALL of mankind will be redeemed from this first spiritual death. Back to Corinthians, "as in Adam all die" spiritually, i.e. by coming to earth are outside of the presence of God, "even so in Christ shall all be made alive" by being brought back into the presence of God i.e. "the atonement bringeth to pass the resurrection of the dead; and the resurrection of the dead bringeth back men into the presence of God; and thus they are restored into his presence, to be judged according to their works" (Alma 42:23). The Atonement really is universal, the "return to God's presence overcame the first spiritual death triggered by Adam, and thus, all that was lost by the Fall was equally restored by the Atonement" and the consequences of "original sin" are overcome for all. (Tad R. Callister, The Infinite Atonement).
And it is in being "judged according to their works" like Alma taught that the second death that Samuel referred to will come about for those who "repenteth not."
This is where the idea of "works" comes in... "The Atonement corrects the first spiritual death for all men without any effort on their own, and understandably so, for they in no way were its cause. The Atonement corrects the second spiritual death on an individual basis for those who repent, since each of us who has sinned must individually contribute to our own redemption" (Tad. R. Callister, The Infinite Atonement). The keyword there is "contribute" -- we don't cause or make our own redemption, or "correct" it ourselves, we merely contribute our repentance and the atonement "corrects," Christ redeems.
Our "contribution" of repentance means turning our will to Christ. Anything we do is merely a part of submitting our will to his; it's part of becoming like him. Keeping the commandments, serving others, etc. will help us access the grace that we need to live day to day "in the posture of repentance" (Neal A. Maxwell, Testifying of the Great and Glorious Atonement) and thereby avail ourselves to the Atonement and avoid the second spiritual death of permanent separation from God.
p.s. you need to read this book!