The Preaching of the Gospel of the Kingdom

And this gospel of the kingdom will be preached in the whole world as a testimony to all nations, and then the end will come (Matthew 24:14)
Note that it is the Gospel of the Kingdom that is to be preached. It appears that the Gospel of the Kingdom has not been preached since the first century. What we have now is the Gospel of Heaven.
Changing the Gospel to the gospel of Heaven may seem harmless. It is anything but that. When people view eternal residence in a mansion in Heaven with no responsibilities, combined with a doctrine of "grace" that teaches we need do nothing to go to Heaven except "believe in Christ, we have the worst possible approach to the redemption God has to mind.
God's plan of redemption has as its emphasis the changing of man into God's image. Believing that our goal is to go to Heaven by "grace" will not change anyone into God's image.