Heavenly Father wants us all to attain godhood, and he bestowed on us the gift of moral agency because it is needed for beings to progress. But using moral agency means that many of his children will stray from the path to divinity. One day during our premortal existence, Heavenly Father devised a plan by which a small percentage of his children would attain godhood while the vast majority would be condemned to eternal damnation.
A Grand Council was called so that Heavenly Father could present his Plan of Salvation to all of his spirit children. "You have now progressed about as far as you can as spirit beings," he explained. "To continue on the path to godhood, you will need leave my presence for a time, take on a physical body, and live a mortal life that will last somewhere between a few seconds and many decades."
"We will create an earth for you to live on," said Heavenly Father. "You will begin your mortal life there as an infant, and you will not remember your premortal life. This will allow you to be tested to see if you will obey my commandments while not in my presence and while living by faith rather than knowledge."
"During your mortal lives you will experience sickness, pain, persecution, and loneliness, and these experiences will teach you endurance, patience, and charity, and help you appreciate what is good," said Heavenly Father. "It is through sorrow and suffering, toil and tribulation that you will gain the education you need to become more like Heavenly Mother and me."
"When your mortal bodies die," said Heavenly Father, "some of you will have lived righteously enough for your spirit to enter Paradise, a peaceful resting place where you will await the Resurrection and Final Judgment. The majority of you, however, will have your spirits cast into hell where you will be endlessly tortured. My wrath and fiery indignation will be poured out on you."
"At the Resurrection, your spirit will be reunited with a glorified immortal body. Then at the Final Judgment, you will be held accountable for your thoughts and actions during mortal life. You will either be cast into the Outer Darkness where you will suffer eternal torture, or you will be sent to one of the three Kingdoms of Glory. Only those few of you who attain the highest kingdom will live in my presence again and become gods yourselves."
"Because of your weaknesses, all of you will sin during your mortal lives," said Heavenly Father. "This is a problem because those who sin cannot be in my presence, and all of you would become ineligible to return to me. Furthermore, the law of justice demands a penalty be paid for every sin. And not even my mercy can rob the law of justice, and so without a solution, the full weight of justice would fall on you untempered and unsympathetic."
"This is why my plan calls for a Savior," said Heavenly Father. "By the shedding of blood of one who is sinless—through unspeakable agony and suffering—a Savior could satisfy the demands of justice by paying the penalty for all your sins, thereby allowing my mercy to cleanse those who sincerely repent. Only someone born to Earth by the union of a mortal woman and myself can fulfill this role."
"Who will volunteer to be this Savior?" asked Heavenly Father. "I volunteer," said Jesus. All of us, Heavenly Father's spirit children, rejoiced and shouted for joy upon hearing Heavenly Father's plan. We were eager for new experiences and to live a mortal life, even if for only a year or a single day. We knew there would be hardships, sickness, and disappointments, but we were willing to take life as it came, without complaints or unreasonable demands.
Then one of Heavenly Father's exalted angels named Lucifer came forward, saying, "I put forth an alternative plan in which all of you will return to Heavenly Father's presence and not a single one of you will suffer torture in hell. My proposal is to safely conduct you through your mortal lives by simply eliminating your ability to choose to sin."
This new proposal caused disagreement in heaven. Lucifer's plan to limit moral agency would prevent people from committing sins like rape, murder, or torture. It would eliminate the need for a suffering Savior and would not require eternal punishment. All of Heavenly Father's children would return to his presence. On the other hand, the small percentage of those who might become gods themselves in Heavenly Father's plan would be denied that opportunity.
When the two plans were put to a vote, the majority favored Heavenly Father's plan, and Jesus was chosen as the Savior. At this, Lucifer began an open rebellion against Heavenly Father and Jesus, and he was joined by one third of all Heavenly Father's spirit children. This made Heavenly Father sad.
• Smith, Joseph. “The King Follet Sermon” Ensign: The Magazine of The Church of Jesus Christ of Latter-Day Saints, April 1971.
• Gospel Fundamentals, (2002), Chapter Chapter 4: We Are Free to Choose, Part One: Our Life in Heaven with God
• Doctrines of the Gospel Student Manual, (2000), 30–31
• Old Testament Stories, (1980), 6–8
A war broke out in heaven and Michael the archangel was chosen by Heavenly Father to lead the battle against Lucifer and his followers. It was a perilous time and a desperately difficult struggle. In the end it was a grand, triumphal victory for Heavenly Father's side. Lucifer and one third of Heavenly Father's children were thrown out of heaven.
This is how Lucifer became Satan, the Devil, and his followers became his angels. For these sons and daughters of Heavenly Father, there is no forgiveness. For them it would have been better to have never been born. They are denied the right to mortal bodies. Their eternal fate will be to suffer the wrath of God and they will be sent to the lake of fire and brimstone.
This caused great sadness in heaven and they wept over Lucifer for he had been a Son of the Morning. Even though we don't remember our premortal lives, we can be certain that we voted for Heavenly Father's plan and took his side in the war in heaven, because only those who did were given mortal bodies like the one you now have.