It seems to me that there were two stages. One was when Lucifer became Satan, and open rebelled against God. Jude talks about this:

Quote:
And the angels which kept not their first estate, but left their own habitation, he hath reserved in everlasting chains under darkness unto the judgment of the great day. (Jude 6)


The other is what Jesus spoke of in saying "Now is the prince of this world cast down." The cross was the final death knell which defeated the adversary. No being in heaven would pay him an mind after the cross.

Those who wait for the Bridegroom's coming are to say to the people, "Behold your God." The last rays of merciful light, the last message of mercy to be given to the world, is a revelation of His character of love.