The answer: And Jesus said unto them, Verily I say unto you, That ye which have followed Me, in the regeneration when the Son of Man shall sit in the throne of His glory, ye also shall sit upon twelve thrones, judging the twelve tribes of Israel.
Jesus does not take occasion here to explain once more what discipleship comprises; He merely makes a statement, a prophecy as to the future. In the regeneration, in the new birth of the world on Judgment Day, when the kingdom of heaven will be finally completed, when the kingdom of glory shall begin, when the Son of Man will Himself sit on His throne to judge the world in righteousness, then the apostles shall sit upon twelve thrones and take part in the administration of Christ's justice and power upon all believers in Christ, who are the twelve tribes in fact, the true children of Abraham.