Who are the first persons cast into the lake of fire?
The first persons cast into the lake of fire are the beast (the Antichrist) and the false prophet. Revelation 19:20 describes them being taken and cast alive into the lake of fire burning with brimstone, making them the first to inhabit eternal doom without the Great White Throne judgment.
Les explains that this scene in Revelation 19:20 occurs at the end of the tribulation, when the King and the Kingdom are about to come on the scene. The beast is the Antichrist, and he is taken along with the false prophet—the only place he is named as such. Both are individuals, both men, and both are cast alive into the lake of fire burning with brimstone. They are the first ones to inhabit the eternal doom of the wicked, entering the lake of fire without benefit of the Great White Throne judgment. All other lost will stand before the White Throne and have their moment, but Jesus will say, 'Depart from me, I never knew you.'
And the beast was taken, and with him the false prophet that wrought miracles before him, with which he deceived them that had received the mark of the beast, and them that worshipped his image. These both were cast alive into a lake of fire burning with brimstone.