Luke 1:1-4; John 1:1-18, 17:1-5

We learn from John that in the pre-mortal state -

"...there was war in heaven: Michael and his angels fought against the dragon; and the dragon fought and his angels..." (New Testament Revelation 12:7)

We read in modern revelation that anciently the great patriarchs -

"...Seth, Enos, Cainan, Mahalaleel, Jared, Enoch, and Methuselah, who were all high priests, with the residue of his posterity who were righteous, into the valley of Adam-ondi-Ahman, and there bestowed upon them his last blessing.
54 And the Lord appeared unto them, and they rose up and blessed Adam, and called him Michael, the prince, the archangel." (Doctrine and Covenants Section 107:53 - 54)

Adam, who was father of all nations, fought with his angels fought against the dragon and the dragon -

"...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." (New Testament Revelation 12:8 - 9)

We learn more of what this war in heaven was about as God explained to Moses -

God told Moses –

“…Satan…is the same which was from the beginning, and he came before me, saying—Behold, here am I, send me, I will be thy son, and I will redeem all mankind, that one soul shall not be lost, and surely I will do it; wherefore give me thine honor.” (Pearl of Great Price Moses 4:1)

In contrast, Our Father in Heaven talked of His–

“…Beloved Son, which was [His] Beloved and Chosen from the beginning, [Who] said unto [Him]—Father, thy will be done, and the glory be thine forever.” (Pearl of Great Price Moses 4:2)

Even -

"Also I heard the voice of the Lord, saying, Whom shall I send, and who will go for us? Then said I, Here am I; send me." (Old Testament Isaiah 6:8)

'For I came down from heaven, not to do mine own will, but the will of him that sent me." (New Testament John 6:38)

We receive more incite on this war as the Lord tells Moses –

“Wherefore, because that Satan rebelled against me, and sought to destroy the agency of man, which I, the Lord God, had given him, and also, that I should give unto him mine own power; by the power of mine Only Begotten, I caused that he should be cast down…”
(Pearl of Great Price Moses 4:3)

Even though Satan and one third of the hosts of heaven were cast down, the war continues today. Satan has never veered from his proposal. He continues to fight and exercise his plan of control, compulsion, dominance, for his own honor, power, glory, and gain.

Elder Henry D. Taylor said -
“Here we observe two different personalities and two different motives of operation. Satan would have removed a person’s free agency and he proposed to redeem all mankind by force, for which he wanted the recognition, honor, and glory. The plan of Jesus would allow individuals to make a choice between what they considered to be right and what they felt would be wrong, and recommended that all honor and glory would be attributed to the Father.” (Henry D. Taylor, “The Right to Choose,” Ensign, May 1976, 72)

It becomes clear who the Savior was in the Old Testament as Paul teaches the Corinthians -

"And did all drink the same spiritual drink: for they drank of that spiritual Rock that followed them: and that Rock was Christ." (New Testament 1 Corinthians 10:4)

Even the Savior declared of himself -

"...Verily, verily, I say unto you, Before Abraham was, I am." (New Testament John 8:58)

Which basically means before Abraham, was I, Jehovah.

And then It is revealed to John how all those who kept their first estate, this premortal existence, would be able to keep their second estate -

"...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..." (New Testament Revelation 12:10 - 11)