The Apostles’ idea of the Kingdom of God, indeed the worldview of all Jews of the first century AD, had been that God would restore David’s throne, and Israel would defeat all its enemies and reign as first among the nations of the world, perhaps similar to Great Britain a few centuries ago when her empire stretched around the globe. It was in such a kingdom that the Apostles, John and James, wished to secure the most prominent seats (cf. Mark 10:37), and it was taught that in such a kingdom, the Messiah never died (cf. John 12:33-34).
Nevertheless, Jesus characterized his Apostles as men who had been with him from the beginning and shared in all his trials. The implication is that the Apostles were often persecuted with or because of Jesus. Yet, they stayed with him (Luke 22:28; cf. John 6:67-69), and because they had done so, Jesus appointed (G1303) them a kingdom (Luke 22:29). The Greek word is the same used for making a covenant (cf. Hebrews 8:10; 10:16) or disposing of one’s goods (cf. Hebrews 9:16-17).
The word kingdom in Luke 22:29 has to do with authority or dominion rather than a kingdom or land of our own. It has to do with sharing in the dominion given Jesus in his office as Messiah (Luke 22:29; cf. Revelation 3:21). It has more to do with authority than it has with ruling. A policeman doesn’t rule anything, but he has authority over many people. A medical doctor has no power to rule over others, but he does have authority, and it behooves one in his care to respect that authority.
It seems as though God rules men’s hearts (Luke 17:21), and Jesus does sit there with the Father (Revelation 22:1-2), and we have no authority there, as Jesus’ disciples. Whatever authority he gives us, it cannot be construed to mean we are permitted to rule over the hearts of men (cf. 1Peter 5:3), because God refuses to share his authority with any man (Isaiah 42:8; 48:11). Rather, Jesus spoke of another throne, from which he rules, and it is from there that we derive our authority (cf. Revelation 3:21). Therefore, although Jesus’ disciples have no right to rule the hearts of men, which would be the throne of God, they do have authority pertaining to revealing Jesus as the Messiah to the world, and this is done through service, not through strength or intimidation.
Some, at least the Twelve, will sit upon thrones. They shall judge Israel, but it is implied that gentiles will also be involved in judging the rest of the world (1Corinthians 6:2). Yet, this doesn’t mean the Apostles won’t be involved, too. The inheritance of the disciples of Jesus (cf. Galatians 3:25-29) seems to involve eating at the table of the Lord (Luke 22:30). I suspect that, since the disciples’ thrones or authority is secured by serving others (Luke 22:26-27), and the judgment that will befall others (viz. the Jews in the first century and gentiles later) will be determined by how Jesus’ disciples are treated as they serve. In other words, the thrones upon which Jesus’ disciples sit are the gifts they have been given through the Spirit to serve mankind (cf. Romans 12:6-8).
Each one who is so gifted has authority over his own gift from the Lord (1Corinthians 12:28; 14:32). He has not worshiped the beast, nor his image, nor received his mark. Rather, he, as the Apostles before him, endure the trials of his faith in the Lord, suffering for the witness he bears and reigns, not over others, but in or through Christ until the judgment (cf. Revelation 20:4). Men are accepted or rejected (judged upon death), according to how they have treated Jesus’ disciples and the witness they offer through their service.