What will the twelve do when Jesus is King?
When Jesus establishes His Kingdom and sits on the throne of His glory as King, the twelve will sit upon twelve thrones, judging or ruling the twelve tribes of Israel. This occurs in the regeneration and resurrection. Judas is excluded; the promise is to those who followed Him and have eternal life.
Les explains that Jesus answers plainly here, speaking to Peter and the other eleven, not Judas. He says, 'Verily I say unto you, that you who have followed Me, in the regeneration, and in the resurrection,' when the Son of Man shall sit in the throne of His glory—that is, when He has set up His Kingdom and is now the King. Then the twelve also shall sit upon twelve thrones, judging or ruling the twelve tribes of Israel. Les notes this is plain language: Jesus is telling them they have eternal life, they are His, and Judas is not included.