Although believers were still waiting during Jesus’ ministry for the kingdom of God to arrive, the kingdom was already present for those who opposed Jesus. When Jesus was in conflict with the Pharisees, we are told, “Jesus knew their thoughts and said to them, ‘Every kingdom divided against itself will be ruined, and every city or household divided against itself will not stand. If Satan drives out Satan, he is divided against himself. How then can his kingdom stand? And if I drive out demons by Beelzebul, by whom do your people drive them out? So then, they will be your judges. But if it is by the Spirit of God that I drive out demons, then the kingdom of God has come upon you’” (Matthew 12:25-28, NIV). Also, “But if I drive out demons by the finger of God, then the kingdom of God has come upon you” (Luke 11:20, NIV).
For those enemies of Jesus who sought to discredit his person, ministry and message, the kingdom had already arrived. There was nothing further in it for them other than their condemnation.
As G.K. Beale wrote in his commentary on the book of Revelation (G.K. Beale, NIGTC, The Book of Revelation, p. 67). “After all, Jesus inaugurated his messianic reign in the midst of his own suffering during his earthly ministry.”
The kingdom of God was already in conflict, not only with the people who were rejecting it but with an evil spiritual kingdom. The passage from Matthew shows us there are two spiritual kingdoms contending for human souls. One is of Satan and the other is from God.