What is meant by the theory of the annihilation of the wicked?
It means the annihilation of the existence of those who die without having accepted Jesus Christ as their Lord and Saviour.
Why is the theory of the annihilation of the wicked, supposedly indicated by Revelation 20:14-15, unscriptural and a reprehensible doctrine?
The annihilation of the wicked is not indicated in Revelation 20:14-15 to anyone who reads the whole passage and parallel passages in the Scriptures. The passage reads: "Then Death and Hades were cast into the lake of fire. This is the second death. And anyone not found written in the Book of Life was cast into the lake of fire." The fate of those cast into the lake of fire is not annihilation. There is no Scripture to support such a theory. The Bible clearly teaches that the future destiny of the wicked is a condition of unresting, unending, conscious torment and anguish.
As to its being a "reprehensible doctrine," I would say that I have never known anyone who accepted this doctrine who did not lose power in serving God. I could give examples of men whom God greatly used who have been led to accept this doctrine and who, in consequence, have been in part or altogether set aside as soul winners. If one really believes the doctrine of the endless, conscious torment of the unrepentant, he will work as never before for their salvation before it is too late.
~R. A. Torry~