What is the Gospel That Jesus Preached?

The Kingdom of God or Heaven is the gospel that Jesus Christ preached.
From that time on Jesus began to preach, "Repent, for the kingdom of heaven is near."
Matthew 4:17 
Jesus went throughout Galilee, teaching in their synagogues, preaching the good news of the kingdom, and healing every disease and sickness among the people.
Matthew 4:23
Why Did Jesus Come?

The gospel of the Kingdom is WHY Jesus came.
Jesus replied, "Let us go somewhere else—to the nearby villages—so I can preach there also. That is why I have come."
Mark 1:38
Although the Kingdom of God is mentioned 116 times in scripture (NIV), it's not the gospel the church preaches today. The church preaches: born again (mentioned only 3 times), the cross, holiness, prosperity etc.. While these are important subsets they are NOT the gospel Jesus preached to the masses. Jesus preached the Kingdom of God.
Jesus went into Galilee, proclaiming the good news of God. "The time has come," he said. "The kingdom of God is near. Repent and believe the good news!"
Mark 1:14-15
Is There a Gospel of the Kingdom?
If there is a Gospel of the Kingdom, why do modern preachers preach the gospel of Jesus Christ, rather than the gospel that Jesus Christ preached?
Mostly because they have not understood that there was a message of the Kingdom, opting to view the words “Kingdom of God” as a mere label housing the collective teachings of Jesus.
If there is a Gospel of the Kingdom, what is it?
Understanding the Gospel of the Kingdom begins by understanding the REASON Jesus died.
Did He die to save us from our sins?  Yes.  Did He die so we would go to heaven?  Yes.  But even these do not explain the reason God sent Christ.
The Bible is actually a LOVE STORY about a King and His citizens. God placed man on earth to rule over His earthly domain.  But something happened.  Through treachery man lost control of the Kingdom.  The Bible is about a Heavenly King and what He did to recapture the Kingdom and restore man to it.
The PURPOSE of the cross was to restore man TO something not just save him FROM something.
The reason Jesus died was to take back the Kingdom Adam lost to Satan in the garden.  God was restoring man to a position of STEWARDSHIP through the Lordship of our King Jesus Christ.
This is the gospel of the Kingdom.  This is the gospel that Jesus preached.  So through Jesus we see that the cross is not so much about Heaven as it is about God’s Kingdom on EARTH.
What needs to be understood is the PROCESS God chooses to restore the Kingdom.  This process is reflected in the nature of the King.
Christ reveals Himself in two ways:
Christ Reveals Himself as Suffering Servant
He was despised and rejected by men, a man of sorrows, and familiar with suffering. Like one from whom men hide their faces he was despised, and we esteemed him not.Isaiah 53:3
It is through the suffering of Christ that spiritual birth is possible.  When man REPENTS of his sin and BELIEVES in the atoning WORK of Christ, he receives a new nature and is born into the Kingdom of Heaven.
Christ restores the Kingdom INTERNALLY through us first.
Once, having been asked by the Pharisees when the kingdom of God would come, Jesus replied, "The kingdom of God does not come with your careful observation, nor will people say, 'Here it is,' or 'There it is,' because the kingdom of God is WITHIN you."Luke 17:20-21
What does the internal kingdom look like, as we walk it out on earth?  What can you expect?
1.  You can expect to suffer.  That’s because the internal kingdom reflects the nature of the King.
Suffering is not an exciting prospect.  But suffering is necessary if you are going to walk out the life of Christ.  Consider the sufferings of Christ.
When they hurled their insults at him, he did not retaliate; when he suffered, he made no threats.  Instead, he entrusted himself to him who judges justly.  “He himself bore our sins” in his body on the cross, so that we might die to sins and live for righteousness; “by his wounds you have been healed.”
1 Peter 2:23-24
It is not easy to live the Kingdom internally.  When people “hurl their insults” at you, what will you do?  Will you return insult for insult or will you return insult with kindness?  This is a painful process.  Suffering is what happens when good and evil collide— in our own lives and in dealing with other people.
But this is what sanctification is about.  It’s about appropriating who we are in heaven (a justified spirit) with who we are on earth (a fallen soul).  It’s about Christ living His life through us and purifying us (see my article, The Process of Sanctification: Bringing Holiness To Your Life). Suffering for good is what the Bible says we are called to do:
If you suffer for doing good and you endure it, this is commendable before God.  To this you were CALLED, because Christ suffered for you, leaving you an example, that you should follow in his steps.
1 Peter 2:20-21
I have been crucified with Christ and I no longer live, but Christ lives in me.  The life I live in the body, I live by faith in the Son of God, who loved me and gave himself for me.
Galatians 2:20
If we confess our sins, he is faithful and just and will forgive us our sins and purify us from all unrighteousness.
1 John 1:9
But some people will worry about their rights— about enabling abuse.  This is what the Bible says about that:
Do not take revenge, my dear friends, but leave room for God’s wrath, for it is written: “It is mine to avenge; I will repay,” says the Lord.  On the contrary: “If your enemy is hungry, feed him; if he is thirsty, give him something to drink.  In doing this, you will heap burning coals on his head.”  Do not be overcome by evil, but overcome evil with good.
Romans 12:19-21
 2.  You can expect peace and joy.
When we learn to submit ourselves to the will of God through suffering we will experience great peace and joy.
Peace and joy is what happens when you OVERCOME.  When you learn to deal with life, rather than life dealing with you.  The Apostle Paul speaks about this in the following scripture:
I have learned the secret of being content in any and every situation, whether well fed or hungry, whether living in plenty or in want.  I can do everything through him who gives me strength.
Philippians 4:12-13
In all things we are more than conquerors through him who loved us.
Romans 8:37
Some people strive to be happy, but happiness depends on circumstances.  With joy it doesn’t.  Joy exists in spite of circumstances.  Joy comes from an inner confidence that emerges as you learn to trust God— you know He is looking out for you.  Peace is it’s natural result.
Do not be anxious about anything, but in every situation, by prayer and petition, with thanksgiving, present your requests to God.  And the PEACE of God, which transcends all understanding, will guard your hearts and your minds in Christ Jesus.
Philippians 4:6-7
3.  You can expect fruit.
Fruit is the end result of the internal kingdom.  Fruit takes time.  As God washes sin out of your life, as He is expressed in you— fruit will appear.  A changed relationship.  Improved finances.  Inner confidence.
Fruit appears in season:
Blessed is the man who does not walk in the counsel of the wicked or stand in the way of sinners or sit in the seat of mockers.  But his delight is in the law of the LORD, and on his law he MEDITATES day and night.  He is like a tree planted by streams of water, which yields its fruit IN SEASON and whose leaf does not wither.  Whatever he does prospers.
Psalm 1:1-3
Christ Reveals Himself as a Conquering King
At the end of the age Christ will reveal Himself as a Conquering King.  He will establish a Kingdom on earth for all to see.  The Kingdom will be EXTERNAL.
The kingdom of the world has become the kingdom of our Lord and of his Christ, and he will reign for ever and ever.
Revelation 11:15
We will rule with Him.  He will reveal us to the world.
The creation waits in eager expectation for the sons of God to be revealed.
Romans 8:19
This will happen in the twinkling of an eye as our bodies are CHANGED incorruptible at the last trumpet.
Brothers, I tell you this: flesh and blood cannot inherit the kingdom of God, and corruption cannot inherit incorruption. Listen!  I am telling you a mystery: We will not all fall asleep, but we will all be CHANGED, in a moment, in the twinkling of an eye, at the last trumpet.  For the trumpet will sound, and the dead will be raised incorruptible, and we will be changed.
1 Corinthians 15:50-52
This is the Gospel of the Kingdom that Jesus preached.  It should also be the gospel that we preach.
We need to seek the Kingdom.
“Seek first the Kingdom of God and His righteousness and all these things will be added to you.”
Matthew 6:33
Our message is two fold.  We preach the Kingdom— INTERNAL.  We ask God to reveal His nature in us.  Through this nature we change the world.
We preach the Kingdom— EXTERNAL.  One day Jesus is coming again and the sons of God will be revealed.
Maranatha!  Jesus come soon.