This post was inspired by On Satan in the Book of Mormon by Kevin Barney at By Common Consent. Kevin's post points out that the Book of Mormon presents an post-Jewish-exile-OT and NT concept of Satan and asks if there are any pre-Jewish-exile sources that support the NT/BOM concept of Satan.
We also must remember that Israel at the time of Jesus to now were in a state of Apostasy. Therefore, the Bible likely accrued unfortunate inclusions and exclusions. Several examples include an excluded section from 1Samuel and the apocryphal Book of Jasher now translated by Donald Parry and JH Parry, respectively, from Dead Sea Scroll Papyrus. Consequently, we don’t know if OT teaching about Satan, as currently found, really reflects what the pre-exile Israelites understood about the nature of the adversary.
And, we shouldn’t forget that Israel rebelled against Moses and refused the higher law, which the patriarchs like Enoch, Noah, Abraham and Melchesidek enjoyed. Consequently, they were given a preparatory law (the Law of Moses) to prepare them to receive the higher law of Christ at his coming. According to the Pearl of Great Price Book of Moses, we understand that the Patriarchs were the first Christians and had revealed to them the true nature of both Christ and Satan. Also, I think modern Christianity is guilty of being kinda arrogant. We assume we know so much more about the nature of God than the ancients. I think we errently conclude that since the Israelites were under the preparatory Law of Moses that the Patriarchs like Enoch, Noah, Abraham, and Melchesidek new even less about the God than Israel. Unfortunately, we don’t know what they believed because the Bible starts with Moses.
According to the Pearl of Great Price book of Moses and Abraham, we realize that Adam was the first Christian. Adam was taught about the mission of Jesus Christ, was baptized, and was able to receive the blessings of the Atonement of Jesus Christ even before it had happened (Christ is the Lamb slain from the foundation of the world). The Book of Mormon also teaches that the people could have a hope in Christ as if he had already come.
Also, we must remember that Christ is called a High Priest after the order of Melchesidek. This points out that the priesthood of the patriarchs like Adam, Seth, Enoch, Noah, Abraham and Melchesidek is of a higher and “more excellent” order than the Priesthood of Aaron (of John the Baptist) which was in general operation to administer the Law of Moses. The Priesthood of Aaron has the authority to baptize with water, but the Melchesidek priesthood has the power to baptize with fire and the Holy Ghost. Accordingly, Jesus Christ didn’t establish a new order of priesthood but restored the higher priesthood and knowledge, as it existed anciently.
There is pre-exile-OT teaching that supports the NT concept of Satan. Isaiah prophesies of the future destruction of Babylon by comparing it’s fall to the Fall of Lucifer from the heavenly council to Earth (who became Satan) and the eventual fall of Satan from Earth to Outer Darkness. Satan and the angels that follow him will not be joined with their mortal followers because through Christ, even the wicked will be resurrected (resurrection of just and unjust of those who kept their first estate). (See Isa. 14: 12-16).
John the Revelator continues the vision of Lucifer fall from Heaven during the Great War in Heaven, which continues on the Earth in which he draws “a third part” of our brothers and sisters with him. (See Rev. 12: 4).
I recognize that all this may be difficult to follow because there are quite a number of new concepts for non-LDS including: anti-mortal existence, heavenly council, Lucifer->Satan, War in Heaven, literal physical resurrection, ect.