Commentaries:
This section shows that the Devil is the diabolical source of sin, that God's enmity against Satan is absolute, and that His enmity lies at the heart of His commitment to rescue man from Satan. He is doing it! He will do it! The major battle is already over: Christ defeated Satan. We are part of the mopping up operations, but the war goes on.
God will destroy. "Destroy" does not mean obliterate in the English sense, but it means "to break the power of." As an angelic being, Satan is not going to be destroyed in the way we think of destruction, but his power over mankind is absolutely broken because of what Christ did! He is still alive; He is still working, because God's plan, which we are part of, is being worked out. If we remain faithful, we will be victorious as Christ was.
On the other hand, if we use the English meaning of "destroy," God will destroy what Satan produces. He will destroy the system of this world that is against God. We know that in the Lake of Fire, God will destroy all of mankind that is unrighteous too.
John W. Ritenbaugh
Satan (Part 5)