John the baptist was sent forth before Christ to preach the good news of the  kindom of God. When Jesus came, He too preached the good news of the kindom of God and taught His disciple how to pray for the kindom of God to come.(matt 6:9-10).

Thus , what I know is that " The kingdom of God is a government established by Jehovah God himself with a choosen king .  This king is Christ Jesus who is greater than all human rulers and is called "the King of those who rule as kings and Lord of those who rule as lords" (1 Timothy 6:15) he has the power to do far more good than any human ruler, even the best among them.

So in the kindom of God where Jesus shall reign, there will be peace, joy, health and no more sorrow. This kindom will be like paradise where every human being unite together. all will be one in Christ Jesus, and peace shall reign in this kindom forever.