banned for Hebrew literally translates Shaitan as The Adversary, but it doesn't mean the adversary of God as much as man. In Judaism, he never fell, rather he's an angel charged with presenting a man's sins before God upon death, something of a prosecuting attorney. The idea is that God is forgiving and tends to give us the benefit of the doubt.
The Jewish reading is that evil originates with man, not an external being. Although it has been surmised that the serpent is the Adversary in disguise, it's not as a cruel being attempting revenge. Think of this way: God creates man and gives them free will, which blinds him to any ability to predict our future, in spite of omniscience. God tells Adam and Eve to do something and they do it. He automatically assumes they're doing it because they're good. The Adversary proposes that man is not purely good, rather that it has yet to know the full realm of its possibilities. It's like having one person in your life tell you what you should do without any other influence. As something of a test, The Adversary introduces a second option, one which goes against God's wish. Man goes that route, which God doesn't take too well, but it is still man's choice. This introduces the first concept of evil, which not only convinces God that man is not deserving of reward unless he earns it, but also tells him that things like mortality are necessary components to educating a creature with free will. Imagine how slow we would be to learn if there were no consequences, such as death? Man is not wholly damned. There is no Hell in Judaism, but when one goes to Heaven, there is a potential distance the spirit will reside from God. The more sin, the greater the distance, and thus the less fulfilling Heaven is. Heaven is not inherently all pleasure. The other option is the Grave, when one has done things so unspeakable that their soul is removed from existence, considered the ultimate punishment. What the limit to this is still under debate. And keep in mind that the idea of the Messiah, in Judaism, is not to take on the sins of man, as each is responsible for his sins only, not those of his parents or ancestors, despite their sins shaping the world he lives in. Man has no need to collectively repent for the fruit of knowledge. This idea was later adopted by certain branches of Christianity, largely from Germanic heritage.
