“Blessed are those who are persecuted for righteousness’ sake, for theirs is the kingdom of heaven.”
This verse is part of the Lord’s teaching known as the Beatitudes. It is an encouragement to those who are under an oppressive, unjust, and cruel treatment because of their faith in Jesus. Without such a promise one would ask himself “Why am I suffering? Is it in vain?” But the words of Jesus are a promise that standing for the righteousness of God in this world has a great reward — the kingdom of heaven, where eternal righteousness and justice reigns. It is theirs, it is their home, their inheritance. They will live in it, they will be its rulers. It is at their will as they have aligned it with God’s will when it was not easy to do so. Standing with righteousness against the unrighteous, and paying a price has also a great reward.
A second notion is that wherever there is a kingdom there is justice. So the suffering under the persecution of the wicked kingdoms of this world, will be redeemed with the reward of heaven for those who are faithful.