LDS believe that the spirits of all men existed before coming to this world. We weren't just created in this life but lived as spirit children of God before coming here.
Before the earth was created, there was a war in heaven. Michael and his angels fought against Satan. 1/3 of the hosts of heaven followed Satan and the other 2/3 followed God.
Revelation 12:3-4, 7-12
3 And there appeared another wonder in heaven; and behold a great red dragon, having seven heads and ten horns, and seven crowns upon his heads.
4 And his tail drew the third part of the stars of heaven, and did cast them to the earth: and the dragon stood before the woman which was ready to be delivered, for to devour her child as soon as it was born.
7 And there was war in heaven: Michael and his angels fought against the dragon; and the dragon fought and his angels,
8 And prevailed not; neither was their place found any more in heaven.
9 And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him.
10 And I heard a loud voice saying in heaven, Now is come salvation, and strength, and the kingdom of our God, and the power of his Christ: for the accuser of our brethren is cast down, which accused them before our God day and night.
11 And they overcame him by the blood of the Lamb, and by the word of their testimony; and they loved not their lives unto the death.
In these verses we see that there was a war in heaven between Michael and Satan (v 7). We learn that Satan wasn't alone but had his angels (v 7,9). Michael was also not alone but had his angels (v 7). Satan and his angels were cast out of heaven into the earth (v 9). Who were these beings in heaven that were warring? Verse 10 has a being exclaiming that Satan was accusing our brethren before God day and night. The brethren were those on the side of Michael who fought against Satan and his angels. Verse 11 is the interesting verse. It tells us that these brethren, who fought on the side of Michael, overcame Satan and his angels by the blood of the Lamb. The Lamb is Jesus Christ who shed his blood as an atonement for our sins. But who is in need of the blood of the Lamb? Is it not the sinners? Sinners do not exist in heaven with God. Once Adam and Eve sinned they were no longer allowed in the presence of God. So these brethren who fought on the side with Michael came down to this earth as mortals and needed the blood of the Lamb to overcome Satan. These very beings who existed before the world was and fought valiantly with Michael for the cause of righteousness, came down to this earth to overcome Satan eventually by the blood of the Lamb. The war in heaven, before the foundation of this earth, was a war between Satan and his angels and those of us who have come to earth and received a body. We all were among the valiant in heaven who fought against the devil. We existed before this world was created as the spirit children of our Father in heaven.
Before the earth was created, there was a war in heaven. Michael and his angels fought against Satan. 1/3 of the hosts of heaven followed Satan and the other 2/3 followed God.
Revelation 12:3-4, 7-12
3 And there appeared another wonder in heaven; and behold a great red dragon, having seven heads and ten horns, and seven crowns upon his heads.
4 And his tail drew the third part of the stars of heaven, and did cast them to the earth: and the dragon stood before the woman which was ready to be delivered, for to devour her child as soon as it was born.
7 And there was war in heaven: Michael and his angels fought against the dragon; and the dragon fought and his angels,
8 And prevailed not; neither was their place found any more in heaven.
9 And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him.
10 And I heard a loud voice saying in heaven, Now is come salvation, and strength, and the kingdom of our God, and the power of his Christ: for the accuser of our brethren is cast down, which accused them before our God day and night.
11 And they overcame him by the blood of the Lamb, and by the word of their testimony; and they loved not their lives unto the death.
In these verses we see that there was a war in heaven between Michael and Satan (v 7). We learn that Satan wasn't alone but had his angels (v 7,9). Michael was also not alone but had his angels (v 7). Satan and his angels were cast out of heaven into the earth (v 9). Who were these beings in heaven that were warring? Verse 10 has a being exclaiming that Satan was accusing our brethren before God day and night. The brethren were those on the side of Michael who fought against Satan and his angels. Verse 11 is the interesting verse. It tells us that these brethren, who fought on the side of Michael, overcame Satan and his angels by the blood of the Lamb. The Lamb is Jesus Christ who shed his blood as an atonement for our sins. But who is in need of the blood of the Lamb? Is it not the sinners? Sinners do not exist in heaven with God. Once Adam and Eve sinned they were no longer allowed in the presence of God. So these brethren who fought on the side with Michael came down to this earth as mortals and needed the blood of the Lamb to overcome Satan. These very beings who existed before the world was and fought valiantly with Michael for the cause of righteousness, came down to this earth to overcome Satan eventually by the blood of the Lamb. The war in heaven, before the foundation of this earth, was a war between Satan and his angels and those of us who have come to earth and received a body. We all were among the valiant in heaven who fought against the devil. We existed before this world was created as the spirit children of our Father in heaven.