Whilst in the Book of Mormon Lehi teaches:
"And now, behold, if Adam had not transgressed, he would not have fallen; but he would have remained in the garden of Eden. And all things which were created, must have remained in the same state which they were, after they were created; and they must have remained for ever, and had no end. And they would have had no children; wherefore, they would have remained in a state of innocence, having no joy, for they knew no misery; doing no good, for they knew no sin. But behold, all things have been done in the wisdom of Him who knoweth all things. Adam fell that men might be; and men are, that they might have joy. And the Messiah cometh in the fulness of time, that he may redeem the children of men from the fall. And because that they are redeemed from the fall, they have become free for ever, knowing good from evil; to act for themselves, and not to be acted upon, save it be by the punishment of the law at the great and last day, according to the commandments which God hath given. Wherefore, men are free according to the flesh; and all things are given them which are expedient unto man. And they are free to choose liberty and eternal life, through the great mediation of all men, or to choose captivity and death, according to the captivity and power of the devil; for he seeketh that all men might be miserable, like unto himself."—2 Nephi, ii, 22-27.
In the same book it is written:
"Yea, I know that ye know, that in the body he shall show himself unto those at Jerusalem, from whence we came; for it is expedient that it should be among them; for it behooveth the great Creator that he suffereth himself to become subject unto man in the flesh, and die for all men, that all men might become subject unto him. For as death hath passed upon all men, to fulfil the merciful plan of the great Creator, there must needs be a power of resurrection, and the resurrection must needs come unto man by reason of the fall; and the fall came by reason of transgression; and because man became fallen, they were cut off from the presence of the Lord. Wherefore it must needs be an infinite atonement. Save it should be an infinite atonement, this corruption could not put on incorruption. Wherefore, the first judgment which came upon man must needs have remained to an endless duration. And if so, this flesh must have laid down to rot and to crumble to its mother earth, to rise no more. O the wisdom of God! his mercy and grace! For behold, if the flesh should rise no more, our spirits must become subject to that angel who fell from before the presence of the eternal God, and became the devil, to rise no more."—2 Nephi, ix, 5-8.
There is a principle developed in the above quotation to the effect that death was "passed upon all men to fulfill the merciful plan of the great Creator;" and furthermore, that the resurrection came "by reason of the fall." For if man had not sinned, there would have been no death, and if Jesus had not atoned for the sin, there would have been no resurrection. Hence these things are spoken of as being according to the merciful plan of God. This corruption could not have put on incorruption, and this mortality could not have put on immortality, for, as we have elsewhere shown, man by reason of any thing that he himself could do or accomplish, could only exalt himself to the dignity and capability of man and therefore it needed the atonement of a God, before man, through the adoption, could be exalted to the Godhead.
Again, if the body could not have been resurrected, it would have had to "crumble to its mother earth," and remain in that condition without the capability of ascending to the Godhead: and furthermore, not only would our bodies have lost their entity, their life and power, but the spirit also would have been placed in a state of subjection "to that angel who fell from before the presence of the eternal God, and became the devil," without a capability or even hope of life, salvation and exaltation, and would have been deprived of all free agency and power, and subject to the influences, dominion and eternal destruction of Lucifer, the enemy of man and of God. Hence, on this ground, and because of the terrible effects which would have resulted to humanity from the proposed plan to deprive man of his free agency, and in seeking to do away with the atonement, Lucifer was cast out of heaven, as were also those associated with him in the same diabolical plans and purposes.
The testimony of the Book of Doctrine and Covenants is in full accord with the revelations in the ancient scriptures. In it we are instructed that God "created man, male and female, after his own image and in his own likeness created he them, and pave unto them commandments that they should love and serve him, the only living and true God, and that he should be the only being whom they should worship. But by the transgression of these holy laws, man became sensual and devilish, and became fallen man. Wherefore the Almighty God gave his Only Begotten Son, as it is written in those scriptures which have been given of him. He suffered temptations, but gave no heed unto them; he was crucified, died, and rose again the third day; and ascended into heaven, to sit down on the right hand of the Father, to reign with almighty power according to the will of the Father."—Doc. and Cov., sec. xx, 18-24, p. 123.
Again, we read from the same source:
"Behold, I gave unto him that he should be an agent unto himself; and I gave unto him commandment, but no temporal commandment gave I unto him, for my commandments are spiritual, they are not natural nor temporal, neither carnal nor sensual."—Doc. and Cov., sec. xxix, 35, p. 146.
"Wherefore, it came to pass that the devil tempted Adam, and he partook the forbidden fruit and transgressed the commandment, wherein he became subject to the will of the 'devil, because he yielded unto temptation. Wherefore, I the Lord God caused that he should be cast out from the garden of Eden, from my presence, because of his transgression, wherein he became spiritually dead, which is the first death, even that same death, which is the last death, which is spiritual, which shall be pronounced upon the wicked when I shall say, Depart, ye cursed. But, behold, I say unto you, that I the Lord God gave unto Adam and to his seed that they should not die as to the temporal death, until I the Lord God should send forth angels to declare unto them repentance and redemption, through faith on the name of mine Only Begotten Son. And thus did I, the Lord God, appoint unto man the days of his probation; that by his natural death he might be raised in immortality unto eternal life, even as many as would believe."—Doc. and Cov., xxix, 40-43, p. 147.