Why does God allow Satan to live?
This is one of the questions that I try to answer in Spectacular Sins. And it is not just something on top of what is already said in the book, but it is right at the heart of it.
But before I answer it, let's make sure that we agree that it is true that God could take Satan out anytime he chose. Because I think there are some who would say, "He really can't, because of some rights (or authority, independence, free will, etc.) that Satan has." But the reason I know God can take Satan out without turning me into an automaton or breaking any rules is because he is going to take him out. He is going to throw him in the lake of fire.
And the question is, "Why didn't he do it yesterday? If he had done it yesterday I wouldn't be tempted the way I am today. The Bible says, 'Lead me not into temptation.' Well, the best way not to be led into temptation is to take the Tempter away! Isn't it? Take him out! I've got sin in my life plenty enough to make me struggle. I don't need Satan on top of my sin making my life more miserable. So God, take him out! You have the right and the power to take him out. You're doing nobody wrong when you take him out. Take him out!"
And he doesn't do it. Why?
The Bible doesn't answer why directly, so we have to go on inferences. But here is my best shot:
God has ordained that Satan have a long leash—with God holding onto it—because he knows that when we walk in and out of those temptations, struggling both with the physical and moral effects that they bring, more of God's glory will shine in that battle than if he took Satan out yesterday.
There will be evidences of God's patience with us and of his mercy towards us as we struggle with sin. And there will be evidences of his sustaining grace as we go through horrific physical suffering that Satan was the immediate cause of (as it says in the Bible: "This woman . . . whom Satan bound for eighteen years" [Luke 13:16]. She had this bent-over back, and Satan was doing it, and God was ordaining that he be allowed to do it). God ordains all of these things so that his glory—his mercy, justice, grace, wisdom—would shine more brightly.
Now we can argue with that and say, "I don't agree. I don't think God should run the world this way." And if we ultimately disagree then we will reject God, we will reject the biblical testimony, and we will perish forever in hell. But I choose to trust him that his way of managing the devil and managing evil that comes at me is wiser than the way I might choose to manage it.
Perhaps the other thing I should say is that he sent his Son right into the middle of this satanic warfare. It was Satan that put it into the heart of Judas to betray him. So Jesus exposes himself to the horrors of Satan's deceit and lies and murder—"He was a murderer from the beginning . . . [and] a liar" (John 8:44)—and dies, in order to make a public display of the principalities and powers in his defeat of them (Colossians 2:15).
There is more glory that will come to Jesus Christ by his suffering to destroy Satan than by powerfully shooting Satan in the head. And there is more glory that will come to Jesus Christ by our sharing in the sufferings of Christ—holding onto his supreme value—than if we had been able to say, "Satan, Depart!" and never have another problem.
And I think the reason for that—this is my ultimate final answer—is that the glory of God and Christ shines more brightly when we are seen to be supremely satisfied in Christ in spite of Satan's torments, rather than if we had his torments removed and liked Jesus because of it.
It's when you love Jesus in spite of Satan's torments and through them that his glory shines most brightly, rather than when we have life made easier for us by Satan's removal and we like Jesus because of it.