Throughout the Bible we read and learn of the presence of Satan in the world as if he had a right to be here and ply his trade of wickedness. Why should a righteous God permit the devil's continued presence and works of evil upon mankind on this planet?
In discussing this matter with a life-long Christian friend of mine, he came up with a valid overview of the situation as follows:-
(Quote) I don’t think there is a short answer. Of course, God could have dealt with Satan any way he liked. But here is my brief thinking on the matter.
Firstly, Satan is God’s creation – a created (not begotten) son of God. (Job 1:6) “Now there was a day when the sons of God came to present themselves before the LORD, and Satan also came among them.” He is not a creation that came out of a dualism of natures, good and evil. He was created out of the unity of God. I think this is the crux – the UNITY of God. We see in the OT how God even used Satan to test and try His people. He tempts Job only by divine permission, so God is always in control, just as in similar instances with David (1Chr 21:1) etc.
Secondly, and this is my best shot right now, because Satan was created a being with a free will, just like we are, he is being left for a limited time (entirely within God’s control) so that we would have free choice. I don’t believe God wants robots who love Him because he manipulates their wills. He wants us to willingly accept Him and love Him. So there must be choice. Satan is the alternative. Choose good or choose evil – God or Satan. It is for this time that God allows Satan free reign that we need to choose – it is God’s dispensation. And because Satan rebelled against Him, God now uses Satan to separate the goats from the sheep.
This could and should be dealt with more deeply, but that is the essence of how I see it. (Unquote)
Indeed, there is no short answer, but what is striking is the fact that God does not spell it out in His Word, the Bible. However, God does say that He will provide answers by revelation through the Holy Spirit. “Howbeit when he, the Spirit of truth, is come, he will guide you into all truth: for he shall not speak of himself; but whatsoever he shall hear, that shall he speak: and he will show you things to come. He shall glorify me: for he shall receive of mine, and shall show it unto you. All things that the Father hath are mine: therefore said I, that he shall take of mine, and shall show it unto you.” (John 16:13-15)
The Title Deed
While not claiming this to be a clear-cut, factual reason for the devil's continued presence, it is, nevertheless, the picture that comes to mind and the way I see it.
We all know what happened in the Garden of Eden. God gave man dominion over the Earth. In effect, He gave the title deed to man and man, in turn, gave the title deed to Satan. Therefore, God no longer had it and man no longer had it. Satan then became the “god of the Earth” and “prince of this world”.
Satan even offered the title to Jesus if Jesus would worship him.
Now if God had removed Satan after he had deceitfully usurped dominion over the Earth and attained the title deed in the Garden of Eden, then the title deed to the Earth certainly would not have been left to man in the (non-existing) last will and testament of Satan. And a righteous God certainly would not have illegally seized the title deed. So, the title deed would have been irrecoverable and, therefore, there would have been no point in redeeming a fallen man. Man would have been unredeemable and the Earth would have become an irredeemable piece of real estate.
Satan had to remain in order for man to be redeemed and to orchestrate a legal means of regaining the title deed.
Man versus the devil
It was from man that Satan took the title deed and it was going to have to be man that would take it back, but only a redeemed man would be in a legal position to do so. That's why the “Son the Man”, Jesus, brought about that redemption on behalf of man. We defeated Satan through Christ.
However, as redeemed men we became citizens of Heaven and we longer are of this Earth.
Satan, therefore, still possesses that title deed and all unbelievers remain under his reign. They are in this world and of this world. (Christians are in this world but not of it)
After the rapture and after the return to Earth together with Jesus, redeemed man (in Christ) will regain the title deed and Satan will be bound for a thousand years. Only then will redeemed man, under the Kingship of Christ, once again have dominion over the Earth. Those who have not made the rapture and have made it through the Great Tribulation and the “goat and sheep separation” and live on the Earth in their natural state, will fall under the rule of Christ and redeemed Christians, who will then exist in a glorified state.
A clear and present danger
The fact of Satan's presence is made clear in Eph 6:12. “For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places.”
However, Jesus Christ has destroyed the works of the devil on behalf of man, enabling us to overcome the devil's evil antics. “He that committeth sin is of the devil; for the devil sinneth from the beginning. For this purpose the Son of God was manifested, that he might destroy the works of the devil.” (1John 3:8)
Ignorance or rejection
The world at large is either not familiar with this victory or simply just rejects it in unbelief. For those who do believe recognize that the devil is active, but they have chosen the abundant life. “The thief cometh not, but for to steal, and to kill, and to destroy: I am come that they might have life, and that they might have it more abundantly.” (John 10:10)
So, although the devil remains, his works are ineffective to those who believe and know that is only a matter of time before the title deed is officially handed back. And as ironic as this may seem, had God not permitted his continuance, man would have been doomed forever.
A sword over his head
We can now look at the scenario as follows.
Imagine the world’s most dangerous criminal being brought to trial, convicted, and sentenced in a most unusual way. In laying down the sentence, the judge states: “You have been found guilty of the most heinous crimes imaginable, committed all over the world, leaving people of all walks of life devastated by your cruel and heartless actions against them. This day you are being judged once and for all. Every person in the world can claim victory over you this day. And I decree that insufficient justice will be served by banishing you to jail for life at this point in time. Therefore, you and your gang of thieves, robbers and murderers will remain free to roam the streets of the world where you will be recognized by all and despised by all. This day’s judgement will follow you wherever you go. I herewith, by the power of this judgement, grant authority to all the peoples of the world to make war against you and to overcome you when they see you or sense your presence in their midst. You will flee from all those who resist you. Those who innocently, through ignorance, fall prey to you will be given an opportunity to get their revenge. Those who willingly choose to side with you will eventually join you to banishment for eternity.”
Indeed, we serve a God of Grace and Wisdom.