OK, sorry this is off topic but I'm confused. Where did the Book of Moses come from, or I mean how did it come about? Where did the material for chapter 1 come from for example. It is not in the KJV.
The Book of Moses is part of the Revelations received by the Prophet Joseph Smith. It can be found in a collection of works known as the Pearl of Great Price. Here is a link to the LDS Scriptures:
Scriptures LDS.org
Going back to why we believe having a body is so important is because we believe that God himself has a body of flesh and bones. We know that Jesus upon resurrecting appeared unto his apostles and showed them his resurrected body.
Luke 24:36-43
36 And as they thus spake, Jesus himself stood in the midst of them, and saith unto them, Peace be unto you.
37 But they were terrified and affrighted, and supposed that they had seen a spirit.
38 And he said unto them, Why are ye troubled? and why do thoughts arise in your hearts?
39 Behold my hands and my feet, that it is I myself: handle me, and see; for a spirit hath not flesh and bones, as ye see me have.
40 And when he had thus spoken, he shewed them his hands and his feet.
41 And while they yet believed not for joy, and wondered, he said unto them, Have ye here any meat?
42 And they gave him a piece of a broiled fish, and of an honeycomb.
43 And he took it, and did eat before them.
His resurrected body was made of flesh and bones as verse 39 points out. Some people believe that Jesus is a spirit but this verse shows us that he has a resurrected body. And 1 Corinthians 15 tells us that a resurrected body in incorruptible and immortal.
1 Corinthians 15:53
53 For this corruptible must put on incorruption, and this mortal must put on immortality.
Thus Jesus still has his body and will always have his immortal and incorruptible body. LDS scripture teaches us that when the body and the spirit are join together, they can receive a fullness of joy.
Doctrine and Covenants 93:33
33 For man is spirit. The elements are eternal, and spirit and element, inseparably connected, receive a fulness of joy;
34 And when separated, man cannot receive a fulness of joy.
But it is not Jesus only that has a resurrected body but the Father also. Another LDS verse tells us the following:
Doctrine and Covenants 130:22
22 The Father has a body of flesh and bones as tangible as man’s; the Son also; but the Holy Ghost has not a body of flesh and bones, but is a personage of Spirit. Were it not so, the Holy Ghost could not dwell in us.
One of the great reasons for coming to this mortal life was to receive a body. It is an essential part of the plan of happiness. Resurrection is a basic doctrine of Christ. We will all eventually rise from the dead and receive an immortal and incorruptible body. The book of Hebrews teaches us:
Hebrews 1:1-3
1 God, who at sundry times and in divers manners spake in time past unto the fathers by the prophets,
2 Hath in these last days spoken unto us by his Son, whom he hath appointed heir of all things, by whom also he made the worlds;
3 Who being the brightness of his glory, and the express image of his person, and upholding all things by the word of his power, when he had by himself purged our sins, sat down on the right hand of the Majesty on high;
This verse teaches us that Jesus is the brightness of the Fathers glory and he is in the express image of the person of the Father. In other words, Jesus is exactly like his father in every respect. This would indicate that the Father too has a body of flesh and bones. Man was also created in the image of God.
Genesis 1:26-27
26 And God said, Let us make man in our image, after our likeness: and let them have dominion over the fish of the sea, and over the fowl of the air, and over the cattle, and over all the earth, and over every creeping thing that creepeth upon the earth.
27 So God created man in his own image, in the image of God created he him; male and female created he them.
Our spirits are the literal offspring of God and for this reason the apostle Paul taught:
Acts 17:28-29
28 For in him we live, and move, and have our being; as certain also of your own poets have said, For we are also his offspring.
29 Forasmuch then as we are the offspring of God, we ought not to think that the Godhead is like unto gold, or silver, or stone, graven by art and man’s device.
We are God's children in a very literal sense. The Lord said to David in a Psalm:
Psalms 82:6
6 I have said, Ye are gods; and all of you are children of the most High.
This Jesus also taught when the Pharisees accused him of blasphemy for claiming he was the son of God.
John 10:31-36
31 Then the Jews took up stones again to stone him.
32 Jesus answered them, Many good works have I shewed you from my Father; for which of those works do ye stone me?
33 The Jews answered him, saying, For a good work we stone thee not; but for blasphemy; and because that thou, being a man, makest thyself God.
34 Jesus answered them, Is it not written in your law, I said, Ye are gods?
35 If he called them gods, unto whom the word of God came, and the scripture cannot be broken;
36 Say ye of him, whom the Father hath sanctified, and sent into the world, Thou blasphemest; because I said, I am the Son of God?
In a very literal sense, we are the offspring of God. We are his spirit children who have come to this earth to gain a body and to learn to live by faith.
Hebrews 12:9
9 Furthermore we have had fathers of our flesh which corrected us, and we gave them reverence: shall we not much rather be in subjection unto the Father of spirits, and live?
Gaining a body is a critical reason why we came to this world. It was so important that the Father and Jesus brought about the resurrection of the body for all who receive one so that we will never lose it. We will live forever with our resurrected bodies. God himself and Jesus Christ have bodies of flesh and bones that are immortal and incorruptible. Because without them we could not receive a fullness of joy.