A. F. J. Klijn (Biblical scholar and author) states that the idea of preexistence comes from Judaism, where the idea of the heavenly robe "may be taken from the description of Adam and Eve in paradise." Of course, he refers to the tradition that Adam's nature was like bright light before the Fall, even as the garment is a garment of light, but after the Fall Adam lost his preexistent glory. J. Rendel Harris (another biblical scholar circa 1850) points out that the Odes of Solomon also contain the ideas of "the pre-existent soul that has to leave heaven for earth, and that of the unfallen creation of God, whose environment is changed from a coat of light to a coat of skins." The "garment of skins" became the "garment of light" possibly because the Hebrew [word for] (coat of skins) so closely resembles [Hebrew word] meaning "coat of light." Even so, the Apocryphon of James tells us that when the spirit returns to its heavenly treasure it will become "as you were first, having clothed yourself, you become the first who will strip himself, and you shall become as you were before removing the garment."
The garment also represents the treasure laid up in heaven awaiting the soul's return, and, in this context, the glory of the resurrected body. An ancient Christian writing known as the Ascension of Isaiah states, "The saints will come with the Lord with their garments which are now stored up in the seventh heaven, with the Lord will come those whose spirits are clothed upon." The Book of Enoch is replete with references to garments. In connection with the resurrection the Book of Enoch says, "And the righteous and elect shall have risen from the earth, and ceased to be downcast in countenance. And they shall be clothed with garments of glory, and they shall be the garments of life from the Lord of Spirits." The Manual of Discipline, found among the Dead Sea Scrolls, contains a concept very similar to that of the Book of Enoch:
And as for the visitation of all who walk in this spirit [of truth] it shall be healing, great peace in a long life, and fruitfulness, together with every everlasting blessing and eternal joy in life without end, a crown of glory and a garment of majesty in unending light.
(The Necessity of a Sinless Messiah by Ronald A. Heiner Fn, BYU Studies, vol. 22 (1982), Number 1 - Fall 1982, p.17-)
I can’t help but wonder if this “garment” that our “spirits are clothed upon” is none other than the gift of our physical bodies which clothe our spirits.
Abraham 3:23 And God saw these souls that they were good, and he stood in the midst of them, and he said: These I will make my rulers; for he stood among those that were spirits, and he saw that they were good; and he said unto me: Abraham, thou art one of them; thou wast chosen before thou wast born.
24 And there stood one among them that was like unto God, and he said unto those who were with him: We will go down, for there is space there, and we will take of these materials, and we will make an earth whereon these may dwell;
26 And they who keep their first estate shall be added upon; and they who keep not their first estate shall not have glory in the same kingdom with those who keep their first estate; and they who keep their second estate shall have glory added upon their heads for ever and ever.
If our first estate was the pre-existence, than the reward for righteousness was the physical body which was added upon our spiritual body. Those who chose unrighteousness did not receive that same glory, or the gift of a physical body. It is such a beautiful teaching showing us that our bodies are glorious. When we show our obedience, and sacrifice our will for the will of the Father in this second estate, our physical bodies of glory will be changed to that of glorified resurrected bodies of light, with the power to produce light.
In our fallen world, the power to keep our second estate is only made possible by the sacrifice made willingly by one who did keep His second estate perfectly. He made a sacrifice of the “glory” that was added upon Him so that we all could have the potentially same “glory” He has. We need our bodies.