Why will the Antichrist destroy the great world religious system?
The Antichrist will destroy it to gain full and complete control for himself. Verse 17 indicates God put it in their hearts to fulfill His will, agree, and give their kingdom to the beast until the words of God are fulfilled.
Les explains that the Antichrist will destroy this great world religious system so that he himself can have full and complete control. Revelation 17:17 is cited: God hath put it in their hearts to fulfill His will, and to agree and give their kingdom unto the beast, until the words of God shall be fulfilled—when the seven years finally come to its end. Earlier, Les describes the first three and a half years as much like the time of Christ: they will go through all the rituals and have all the religion aspects, but God will not be in it, because they are still denying the Christ who died for them.