Beginning of the End - Ellen G. White

Why God Did Not Destroy Satan
God could only use methods that were consistent with truth and
righteousness. Satan could use what God could not--flattery and
deceit. So it was necessary to demonstrate before the inhabitants of
heaven and all the worlds that God's government is just, His law
perfect. Satan had made it seem that he himself was seeking to
promote the good of the universe. His true character must be
understood by everyone. He must have time to reveal his true self by
his wicked works.
He declared all evil to be the result of the divine administration
and it was his own purpose to improve God's law. So God permitted
him to demonstrate the nature of his claims, to show the working out
of his proposed changes in the divine law. His own work must
condemn him, and the whole universe must see the deceiver
unmasked.
Why Didn't God Destroy Satan?
Even when Satan was cast out of heaven, Infinite Wisdom did
not destroy him. The loyalty of God's creatures must rest upon a
conviction of His justice and love. At that time, the inhabitants of
heaven and of the world could not have seen the justice of God in
the destruction of Satan. Had he been immediately blotted out of
existence, some would have served God from fear rather than from
love. The influence of the deceiver would not have been fully
destroyed, nor would the spirit of rebellion have been completely
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