THE ERADICATION OF SIN
The Book of Revelation clearly teaches that in the end sin and Satan will cease to exist. When it is all over “There shall be no more curse,” “there shall be no more death, neither sorrow, nor crying, neither shall there be any more pain, for the former things have passed away” (Revelation 22:3, 21:4). Satan and his followers will be “cast into the lake of fire and brimstone” which “shall burn them up,” leaving them “neither root nor branch,” and Satan “shall be no more forever” (Revelation 20:10, Malachi 4:1, Ezekiel 28:19. See also chapter 20).
However, eradicating sin once it has come into existence is not a simple matter. Some have argued that God never should have created beings with the possibility of sin in the first place. But there is far too much that is unknown and incomprehensible for a finite creature to make that kind of judgment. The infinite price of redemption makes it clear that God, who hates sin with its pain and death more than any human possibly can, still considers His creation to be worth all the pain.
If we believe by faith that God was loving, righteous and wise when He created beings with free wills who ultimately sinned, we are led to the painful conclusion that even God cannot stop atrocities and tragedies without taking away the very freedom that He died on the cross to preserve. Instead God endures the pain of seeing His creation suffer, while offering Himself as the remedy to those who will choose to accept Him, all the while working toward the time when sin can effectively be brought to a permanent end.
God has at least two reasons for his temporary toleration of sin. First, He wants to save as many of His children as He can, so they can live with Him forever. And second, He wants to so thoroughly demonstrate the contrast between His principles and the principles of Satan that sin will never rise up again. God “could have” destroyed Satan when he first rebelled, but this would have left his slanderous charges and accusations unanswered. Satan was not alone in his rebellion: "his tail drew a third of the stars [myriads of angels] of heaven," and besides the angels who overtly rebelled, no doubt many others had questions in their minds about Satan's accusations. Even if Satan and all his followers were destroyed, another “Satan” would have arisen, and then another and another, with God destroying them but never proving that they were wrong.
Satan’s every-man-a-law-to-himself sin principle can only be purged by allowing it to work out and demonstrate itself. To stop sin prematurely would mean exercising arbitrary, coercive control on Satan and sinners, the very beings God created to have free choice. Since “all have sinned” and “the wages of sin is death,” God would have to kill all people and rebellious angels in order to put a stop to the pain and suffering that go along with sin. Although He does not do this, He does restrain evil and limit suffering—“Because of the Lord’s great love we are not consumed, for His compassions never fail” (Lamentations 3:22 NIV).
At the end of time, in order to allow the ultimate demonstration of the sin principle, God will briefly withdraw his restraint of the murderous passions and the disasters that are the natural results of sin, ushering in “a time of trouble such as never was since there was a nation” (Revelation 7:1, Daniel 12:1). But in all fairness to the human race, God wants everyone on earth to have a chance to be prepared for that catastrophic experience. This is why Jesus said “this gospel of the Kingdom will be preached in all the world as a witness to all the nations, and then the end will come” (Matthew 24:14). By that time God will have developed full demonstration of His kingdom principles. Through the ministry and the gifts of the Holy Spirit, God’s people will have “come to the unity of the faith and of the knowledge of the Son of God, to a perfect man, to the measure of the stature of the fullness of Christ” (Ephesians 4:7-16).
The contrast between those led by the Spirit and those controlled by sin will be such that there will be an eternal witness to the whole universe of the righteousness of God and the malignity of sin—“to the intent that now the manifold wisdom of God might be made known by the church to the principalities and powers in the heavenly places” (Ephesians 3:10). Sin will come to a permanent end: “The Lord is slow to anger and great in power, and will not at all acquit the wicked…The Lord is good, a stronghold in the day of trouble, and He knows those who trust in Him…The mountains quake before Him, the hills melt and the earth heaves at His presence…He will make an utter end of it. Affliction will not rise up a second time” (Nahum 1:1-9).
 For example, at what point in the chain of events would God interfere to stop someone who had decided to drink until intoxicated and then drive recklessly, with the very real possibility of causing a terrible tragedy? Would he manipulate the person’s mind so that he wouldn’t want to drink, or paralyze his arm so he couldn’t, or change the nature of the alcohol so it wouldn’t have an intoxicating effect, or move cars out of the way of the inebriated driver? Obviously there would be no real freedom of choice in such a world.
 “The heavens and the earth…are reserved for fire until the day of judgment and perdition of ungodly men” because “The Lord…is longsuffering toward us, not willing that any should perish but that all should come to repentance” (2 Peter 3:3-9).
 It is actually illogical to talk about what God “could have” done. God can only act in harmony with His own character of love, and in this sense His sinful creatures can do things that He cannot. For example, “It is impossible for God to lie” (Hebrews 6:18), but sinners can lie, as well as break all of God’s laws. Obviously God cannot break His own law since it is a reflection of His character.