Here are some interesting facts about the Kingdom of God & the Kingdom of Heaven:
1. The Kingdom of God and the Kingdom of Heaven are actually THE SAME THING! The only difference between the two is that Mark, Luke & John used the phrase Kingdom of God in their gospels while Matthew was the only apostle to refer to it as the "Kingdom of Heaven".
For Example, consider these stories where Matthew uses the phrase Kingdom of Heaven. We see that in the corresponding mention of the stories in the other gospels, the term Kingdom of God is used:
Notice that whenever the phrase Kingdom of Heaven is used in the gospel of Matthew, the phrase Kingdom of God appears in the other gospels.
2. The Kingdom of Heaven is NOT HEAVEN:
If I said you are a Child OF God, that would imply that you are not God, but you belong to Him. If I said you are a Student OF Life that would imply that you are not life, but that you are a product of it. Likewise, the term Kingdom OF Heaven is not another name for the term Heaven. It is a reference to Heaven's ruling or governing on the earth: The kingdom that is a product of heaven --- The Kingdom on earth that belongs to heaven. Remember: Jesus said when you pray, pray saying When your kingdom comes your will will be done on earth as it is in heaven.
The Kingdom of Heaven is the reference to Jesus Christ's coming to the earth and ruling over the church (becoming the head of the church). It is Jesus Christ's kingdom which He has been made the head of. Hence, the reason John the Baptist cried out prior to Jesus' coming "Repent, the kingdom of heaven is at hand!". He was referring to the fact that soon Jesus was coming. He was not referring to the the fact that soon people would die and go to heaven or hell. He was advising the people to change their ways so they could follow Jesus Christ; which is the same thing as becoming a part of the Kingdom of Heaven/body of Christ.
Notice that prior to Jesus' ministry the Kingdom of Heaven/Kingdom of God is referred to in the future tense. Then when Jesus began to minister the Kingdom of Heaven/God is referred to in the present tense. (Compare Matthew 3:2 with Matthew18:1-4
3. How is this beneficial to you?
Do you remember the story in Matthew 18:1-4 when the disciples asked Jesus who is the greatest in the kingdom of heaven? Jesus said whoever humbles himself as little children will be greatest in the kingdom of heaven. In this passage, the disciples are asking Jesus which of all the disciples in ministry are the greatest or are regarded the most highly. Jesus says those who humble themselves as children will be referred to as the greatest of the kingdom.
This is a scriptural picture of the fact that those who prophesy, work healing miracles and even speak in tongues in the kingdom of God/body of Christ are those who humble themselves by dying to flesh and yielding to the Holy Spirit. Those who put aside their own knowledge, understanding and know-how and depend on God with child-like faith are the ones who tend to be used to work the greatest miracles... here on Earth! (Not in heaven.)
Furthermore, in Matthew 19: 23 (also found in the other gospels) Jesus says it is easier for a camel to go through the eye of a needle than it is for a rich man to enter into the kingdom of heaven. Does this mean that rich people don't go to heaven? No. Once again, this is a picture of the fact that those who depend on the things of this world and are reliant on flesh-like things are rarely ever used greatly by God here on earth in the body of Christ. Once again, those who are dependent and not self-reliant, but are like children, these are the greatest in the kingdom. There are many rich people who work great miracles and are considered to be great in the kingdom of God. However, these people must have more faith in God than they do in their possessions.
Consider this parable about the kingdom of heaven in Matthew 13:45-46:
45 “Again, the kingdom of heaven is like a merchant seeking beautiful pearls, 46 who, when he had found one pearl of great price, went and sold all that he had and bought it.
Here again, the kingdom of heaven is shown as being so valuable that a person who truly becomes a part of it gives up all that they have: metaphorically referring to their own abilities, will, works etc. They give all of this up to solely depend on God and His kingdom because they understand the value of the kingdom is far greater than the value of their worldly possessions.
So, the kingdom of God and the kingdom of heaven is referring to the "kingdom" on earth where God is manifested to and through His people. People enter into the kingdom of God when they become saved and those greatest in the kingdom are those who humble themselves in the presence of God in order for God to lift them up.
“Blessed are the poor in spirit, For theirs is the kingdom of heaven." -Matthew 5:3