Is the Devil Part of God's Plan?
Let me suppose, for a moment, the possibility that Satan is an essential part of God's plan.
I'm basing this premise on certain scriptures found in Christianity: Job 1:6 finds Satan in the presence of God, where God not only grants him audience, but allows him to test Job. Note that Satan wasn't going to do anything unless God allowed it. This means Satan was subject to - and obedient to - God. Note also, that though Ephesians 5:5 says that no unclean thing can dwell with God, Satan was nevertheless in His presence. Does this mean that Satan is a "clean" soul?
Another curious thing about Job's story: It appears that, in the end, Job became stronger for withstanding all this.
In Exodus 7:3, the Lord promises he will harden Pharaoh's heart, so that he can demonstrate his powers to Israel. Is the Lord saying that he would put some type of rebellion into someone's heart? I thought the Lord did not instigate evil. I would understand, though, if the Lord knew Satan was going to harden Pharaoh's heart, and decided to allow it.
Finally, I submit that God wanted Satan and his angels to tempt us: In Revelation 12:4-5, we see that a dragon's tail drew away a third part of the stars of heaven and cast them to the earth. This is related to verses 7-9 where it shows that the dragon was Satan, and that he and his angels (stars?) were cast down to the earth. Evidently, God allowed the devil and his angels to come to the earth. He, being God, could have prevented it if he wished. In fact, God may have done this himself, as Rev. 12:9 shows that Satan and his angels were "cast out."
Why didn't God send Satan and his angels to Mars, or to Pluto? Why earth? Why not another star system? He sent them here, so that they could tempt us, and therefore so that we could learn to grow in experience, and learn how to distinguish right from wrong.
When you think about it, don't you find that we need resistance, in order to grow stronger? To build muscle, we need an opposing force against those muscles. To gain happiness, we need to experience the sorrow. How can you know and appreciate achievement, if you do not know failure?
I think that if it weren't for opposition, we would be like house cats. They don't seem to find joy in life. They don't seem to know right from wrong. They don't achieve. They don't overcome their natural tendencies and achieve flight or trips to the moon, or they don't find joy in artistic expression.
I don't really know if Satan's presence is part of God's plan. I'm only saying that his temptings and roadblocks can be counted as a blessing for us, especially if we overcome them. The devil and his legions are a tremendous force, as shown in Ephesians 6:12, a power second only to that of God. If we can overcome that power, then we will be stronger than that force.