However, before they could attain perfection, Eve committed fornication with Lucifer. Lucifer and Eve became one in sexual union, causing the spiritual fall of mankind. Eve, hoping to undo her action, persuaded Adam to live with her as her husband, even though he had also not attained perfection. This caused the fall of mankind. Through sexual union, Eve took on the sinful characteristics of Lucifer, and Adam received these sinful characteristics through his sexual union with Eve.
Salvation is basically the undoing of the results of the fall.
The individual has to be restored and perfected, and then enter into a relationship and produce perfect children. To accomplish this, a Messiah or a Christ is needed. Historically, Jesus the Messiah came in David's place to restore mankind. Jesus' purpose in coming was to take a bride in Eve's place, marry and produce perfect children. By the example and power of his family, other perfect families would be formed until the whole of society was restored and in line with God's purpose.