The kingdom of heaven is a central theme which runs through the Gospel of Matthew. The phrase “the Kingdom of Heaven” is used over thirty times in Matthew’s Gospel. Matthew did not want his Jewish readership to misunderstand the nature of the Kingdom. The Jews were anticipating a physical kingdom, not a spiritual kingdom. However, while Jesus was standing before Pilate at His trial, He said, “My kingdom is not of this world.”
In contrast to the condemnation given to false teachers, Jesus offers blessings to members of the kingdom. Jesus begins His Sermon on the Mount by blessing the “poor in spirit, for theirs is the kingdom of heaven”. At the end of the beatitude, Jesus references the kingdom of heaven. This time, He says “Blessed are those who are persecuted for righteousness sake, for theirs is the kingdom of heaven”. In either case, the kingdom is offered to those who put God’s kingdom before their self-interest.
Furthermore, those who disobey this command are like chaff that will be separated from the wheat and burn with unquenchable fire. Therefore, rejecting the kingdom of heaven has eternal consequences. Proclaiming a message that is counter to the kingdom of heaven is condemnable. This is a stern warning, so as to avoid drawing people away from the kingdom of heaven, by presuming that one can enter the kingdom by his righteousness.
The use of the word “heaven” would certainly help emphasize and reinforce the spiritual nature of the kingdom. The scripture explicitly connects the kingdom of heaven with the gospel. When Jesus sends out His disciples, He also commissions them to proclaim, “The kingdom of heaven is at hand”. Significantly, John the Baptist, Jesus, and the disciples all preached the same message and each followed the command to repent. The call to repentance is grounded in the imminent coming of the kingdom of heaven. You must repent because the kingdom of heaven is near.