The "kingdom of heaven" occurs 32 times and only in the book of Matthew. Some theologians believe that Matthew was referring to the "kingdom of heaven" as a millennial kingdom while other authors where referring to a universal kingdom. Many believe this interpretation to be in error. Matthew 19 we see that Christ uses the kingdom of heaven and kingdom of God interchangeably.
The church (body of Christ) is part of the kingdom. The kingdom consists of God, his angels and born again children of God. The kingdom of darkness consists of satan, his angels and men (women) of this world. The kingdom has been opened to man through Christ and the enemy is trying to keep it from you. You are admonished to take it by force. Take all that God has prepared for you by the power of God and in the name of Jesus.