Elder Russell M. Nelson of the Quorum of the Twelve Apostles explained why the Fall was necessary:
“The Creation culminated with Adam and Eve in the Garden of Eden. They were created in the image of God, with bodies of flesh and bone. Created in the image of God and not yet mortal, they could not grow old and die. ‘And they would have had no children’ [2 Nephi 2:23] nor experienced the trials of life. … The creation of Adam and Eve was a paradisiacal creation, one that required a significant change before they could fulfill the commandment to have children and thus provide earthly bodies for premortal spirit sons and daughters of God.
“… The Fall of Adam (and Eve) constituted the mortal creation and brought about the required changes in their bodies, including the circulation of blood and other modifications as well. They were now able to have children. They and their posterity also became subject to injury, disease, and death” (in Conference Report, Oct. 1996, 44–45; or Ensign, Nov. 1996, 33).
President James E. Faust added to the description of how the Fall affected Adam and Eve as well as all their posterity:
“Because of their transgression, Adam and Eve, having chosen to leave their state of innocence (see 2 Nephi 2:23–25), were banished from the presence of God. This is referred to in Christendom as the Fall, or Adam’s transgression. It is a spiritual death because Adam and Eve were separated from the presence of God and given agency ‘to act for themselves and not to be acted upon’ (2 Nephi 2:26). They were also given the great power of procreation, so that they could keep the commandment to ‘multiply, and replenish the earth’ and have joy in their posterity (Genesis 1:28).
“All of their posterity were likewise banished from the presence of God (see 2 Nephi 2:22–26). However, the posterity of Adam and Eve were innocent of the original sin because they had no part in it. It was therefore unfair for all of humanity to suffer eternally for the transgressions of our first parents, Adam and Eve. It became necessary to settle this injustice; hence the need for the atoning sacrifice of Jesus in His role as the Savior and Redeemer. Because of the transcendent act of the Atonement, it is possible for every soul to obtain forgiveness of sins, to have them washed away and be forgotten (see 2 Nephi 9:6–9; Talmage, Articles of Faith, p. 89). This forgiveness comes about, however, on condition of repentance and personal righteousness” (in Conference Report, Oct. 1988, 13–14; or Ensign, Nov. 1988, 12).
President Brigham Young (1801–77) and President Joseph Fielding Smith help us understand that the Fall of Adam was part of our Heavenly Father’s plan:
“Did they [Adam and Eve] come out in direct opposition to God and to his government? No. But they transgressed a command of the Lord, and through that transgression sin came into the world. The Lord knew they would do this, and he had designed that they should” (Discourses of Brigham Young, sel. John A. Widtsoe [1954], 103).
“Adam did only what he had to do. He partook of that fruit for one good reason, and that was to open the door to bring you and me and everyone else into this world. …
“… If it hadn’t been for Adam, I wouldn’t be here; you wouldn’t be here; we would be waiting in the heavens as spirits” (Joseph Fielding Smith, in Conference Report, Oct. 1967, 121–22).
We learn from Moses 5:10–11 that Adam and Eve also recognized blessings from the results of the Fall. They understood the following concepts:
“My eyes are opened.” They knew good from evil (verse 10).
“In the flesh I shall see God.” The Resurrection could take place from the coming of the Lord Jesus Christ (verse 10).
“We … should have … seed.” Procreation came into the world (verse 11).
“We … have known good and evil.” Adam and Eve had the agency to choose between good and evil (verse 11).
“We … have known … the joy of our redemption, and the eternal life which God giveth unto all the obedient.” The Atonement could take place (verse 11).