Who is Satan? What does the Bible say about Satan?
Jesus mentioned that He saw Satan fall from Heaven as lightning (Luke 10:18). Now we all know that lightning is exceeding bright but its light does not last long as it falls down towards the Earth. The implication is that Satan was a light-bearer until he fell from his position of authority.
In the book of Revelation, we read about Satan being cast out of Heaven but this is not what Jesus was referring to at the time he was talking to His disciples. Why? Because if you read the book of Revelation, you will learn that John was prophesying about what was to come, which might include what was happening at that present time, but not what had already taken place.
The book of Revelation states:
The Revelation of Jesus Christ, which God gave unto him, to shew unto his servants things which must shortly come to pass; (Rev 1:1)
After this I looked, and, behold, a door was opened in heaven: and the first voice which I heard was as it were of a trumpet talking with me; which said, Come up hither, and I will shew thee things which must be hereafter. (Rev. 4:1)
And there was war in heaven: Michael and his angels fought against the dragon; and the dragon fought and his angels,And prevailed not; neither was their place found any more in heaven. And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him. And I heard a loud voice saying in heaven, Now is come salvation, and strength, and the kingdom of our God, and the power of his Christ: for the accuser of our brethren is cast down, which accused them before our God day and night. And they overcame him by the blood of the Lamb, and by the word of their testimony; and they loved not their lives unto the death. Therefore rejoice, ye heavens, and ye that dwell in them. Woe to the inhabiters of the earth and of the sea! for the devil is come down unto you, having great wrath, because he knoweth that he hath but a short time. (Revelation 12:7-12)
So we have Jesus saying that Satan lost what he possessed, on the one hand, and on the other hand, we see that Satan still has access to Heaven.
The Book of Job speaks about Satan having access to Heaven and he appears to be able to turn up there after going to and fro around the Earth. This provides us with a picture of Satan having lost his Heavenly authority but still having some Earthly authority and still being permitted access to Heaven and the throne of God. Moreover, we learn from the book of Job that Satan has some issues with Job because there is a hedge that has been placed around Him and this prevents him from touching the man. An accusation is made that Job would not honor God if the hedge was not in place and Satan was not permitted to harm him.
Satan is now the accuser. Satan is accusing God for protecting Job unduly. The implication is that Satan has the right to all that is on the Earth but God is not permitting him to access Job because of the hedge that has been placed around him. Satan accuses God of impartiality. Why? Because Satan has lost his authority in Heaven and now only has authority over the Earth. However, Satan is not permitted authority over Job to do whatever he likes to the man. God permits Satan to exercise his authority on Earth, but prohibits him from taking Job's life biologically. Job has to be made accountable for his life, if the accuser is to accuse him.
Why doesn’t Satan simply kill Job?
The Bible narrative is that Satan has a legal right over the Earth, but he is a created being who only has finite resources. God is infinite and omnipotent. If God so desired He could obliterate Satan and there would be no thought or memory of Him at all.
However, there are issues here concerning righteousness. For God to be righteous, He has to execute justice without impartiality. God cannot become an unreasonable dictator who indiscriminately violates His own rulings. Consequently, everything the Omniscient Creator does has to be executed in accordance to what is right, just and true. For it is only right that justice be true and not corrupted by impartiality (as we see all too frequently in the courts that executive rulings and decisions within the judicial systems on Earth).
Satan himself has to comply with what is right, even though he appears to think that he is imperishable—which is why he is called the Father of Lies. The implication being that Satan does not think God can destroy him, for he is a spirit being just like God is Spirit.
Furthermore, there is no evidence of God having destroyed any of his Creation. Those who say that there is no God believe there is nothing to worry about in respect to death. On the other hand, Satan is prepared to war with God because he believes he has nothing to worry about. Satan cannot see how God can destroy him.
But before this war breaks out in Heaven, when Satan is finally cast out forever, we see this accuser of the brethren accusing God of impartiality because He places a hedge around people. What we see occurring with Job is inferred in the New Testament.
Jesus said that Satan lodged a claim upon the Apostle Peter. The Apostle John in the book of Revelation says that Satan is the accuser of the brethren. From what we read in the book of Job and what is in Revelation and what we find in the First Epistle of John, we get a clear picture of Satan being a prosecutor. This is what the Apostle John states:
My little children, these things write I unto you, that ye sin not. And if any man sin, we have an advocate with the Father, Jesus Christ the righteous. (1 John 2:1)
An advocate is someone who argues another person’s case. In other words, an advocate is a lawyer. Now this leaves us with a picture of Jesus arguing on behalf of sinners before the throne of God while Satan is attempting to prosecute his case against them for their sin. This is essentially what we see happened to Job, except there is no mention of Jesus.
Jesus said to the unbelieving Jews:
You are of your father the Devil, and your will is to do your father’s desires. He was a murderer from the beginning, and has nothing to do with the truth, because there is no truth in him. When he lies, he speaks according to his own nature, for he is a liar and the Father of Lies. (John 8:44).
The Apostle John writes:
He who commits sin is of the Devil; for the Devil has sinned from the beginning. The reason the Son of God appeared was to destroy the works of the Devil. (1 John 3.8)
From the Scriptures mentioned, we learn that Satan is the Devil, the Old Serpent who deceived Eve and who deceives the world. Not only this, the Devil is said to be a murderer (a destroyer). With the knowledge that the Father of Lies sinned in the beginning and brought evil and destruction to bear upon the inhabitants of the Earth, having gained authority over it by stealing the domain from Adam, we see there comes a time when the Devil makes his last accusation at the Throne of God in Heaven and he is cast out. He cannot accuse the brethren anymore when this takes place, which suggests that there is time when the Brethren must overcome sin. In fact, the Brethren overcome Satan by the Blood of the Lamb and the word of their testimony. Satan now wrecks havoc on Earth, but only for a short time. From other Scripture we learn that this is a time evil on the Earth that had never been before, which ushers in the Second Coming of Lord Jesus Christ.
In summary: Satan is a being who sought to violate God’s righteousness for his own ends and appears to have taken hostage the Earth and its inhabitants. The Son of God, Lord Jesus Christ appeared on Earth to destroy the works of the Devil. Therefore, Jesus paid the ransom price to redeem the Earth and its inhabitants. Once the complete number of the captives are finally freed from their captivity and Satan has no claim on them (Romans 11;25), he will be forced out of Heaven and onto Earth with his army. When this occurs, all hell is going to break loose (with Israel being established as a nation against all odds, Atheism becoming rampant, and Islam growing, the time is close). At the return of Jesus, Satan and his angels will be thrown into prison for a thousand years and then released for the final battle, after which will come the Great White Throne Judgment when justice will be executed and righteousness will be restored for eternity. Satan, his legions, and those who side with him and reject God will be thrown into a lake of fire as an eternal memorial to the righteous judgment of the Almighty against sin (Revelation 20)..
While this is not an exhaustive treatment of the subject, it does provide some extra light to that already submitted in answer to the question. There are many more references required even to support the claims in the summary. It would take a book to address the issue in detail (for instance, more about Satan’s fall is provided in the link below).