We seem to see a bit differently what the core of the gospel is, however scripture is clear, jesus said himself that he came preach the good news of the kingdom of heaven or kingdom of GOD, please do a search of the words kingdom of GOD or Kingdom of heaven in the new testamant, you will find a long list of instances where jesus preaches the kingdom of GOD in the first four books of the NT, this is well recorded in scripture
It is also true that, using the words of excellent brother Nehemiah6 in post no 14;
"We preach CHRIST and Him crucified, buried, resurrected, and ascended to Heaven. The focus must always be on Christ Himself, since He is the Way, the Truth, and the Life, as well as the Resurrection and the Life.
Yes we should be preaching this but also we should be preaching the gospel of Jesus the son of GOD who came to preach the good news of the kingdom of heaven this is what he came to do as it is written in scripture;
Mat 10:5 Jesus sent out these twelve, commanding them, saying, Do not go into the way of the nations, and do not enter into
any city of
the Samaritans.
Mat 10:6 But rather go to the lost sheep of
the house of Israel.
Mat 10:7 And as you go, proclaim, saying, The kingdom of Heaven is at hand.
Mat 10:8 Heal the sick, cleanse the lepers, raise the dead, cast out demons. You have received freely, freely give.
Mar 1:14 And after John was delivered up, Jesus came into Galilee, proclaiming the gospel of the kingdom of God,
Mar 1:15 and saying, The time is fulfilled, and the kingdom of God draws near. Repent, and believe the gospel.
Luk 4:43 And He said to them, I must proclaim the gospel, the kingdom of God, to other cities, because I was sent on this
mission,
Jesus was always speaking , teaching on the kingdom of heaven. A quick search with the keywords kingdom of heaven will give you many results, below is one of many, the beautiful sermon on the mount;
Mat 5:2 And He opened His mouth and taught them, saying,
Mat 5:3 Blessed
are the poor in spirit! For theirs is the kingdom of Heaven.
Mat 5:4 Blessed
are they that mourn! For they shall be comforted.
Mat 5:5 Blessed
are the meek! For they shall inherit the earth.
Mat 5:6 Blessed
are they who hunger and thirst after righteousness! For they shall be filled.
Mat 5:7 Blessed
are the merciful! For they shall obtain mercy.
Mat 5:8 Blessed
are the pure in heart! For they shall see God.
Mat 5:9 Blessed
are the peacemakers! For they shall be called the sons of God
Mat 5:10 Blessed
are they who have been persecuted for righteousness sake! For theirs is the kingdom of Heaven.
Mat 5:11 Blessed are you when
men shall revile you and persecute
you, and shall say all kinds of evil against you falsely, for My sake.
Mat 5:12 Rejoice and be exceedingly glad, for your reward in Heaven
is great. For so they persecuted the prophets who were before you.
The Kingdom of Heaven is in my comprehension the core of the gospel of Jesus ,our messiah.
Blessings to all.