Jesus' message was the Kingdom of God

“Since the Kingdom of God was the heart of all that Jesus taught, and since he fully endorsed the hopes of the prophets (Matt 5:17, Rom 15:8,) the removal of the Messianic Kingdom will threaten the substance of Jesus’ Christian message…the teaching of Jesus suffered a devastating blow when expositors no longer acknowledged that the Kingdom of God means primarily and dominantly what it had always meant to the prophets: a “concrete” Kingdom of God on the earth to be initiated by the event known in the Old Testament as the Day of the Lord and in the New as the Second Coming of Jesus. The term “Kingdom of God” on Jesus’ lips is the new order to be inaugurated by his return. This corresponds exactly with the Old Testament’s descriptions of God reigning (i.e., in the person of His chosen King, the Messiah)( Isa. 52: 7-10; 32: 1; Ps. 2; Zech. 14: 9; Rev. 11: 15-18, Ps. 96-101, which describe the day on which “the Lord has become King” — begun to reign). Traditional theology seems to have forgotten that Jesus came to “confirm the promises made to the fathers” (Rom. 15: 8,) and the fathers, beginning with Abraham, were expecting to “inherit the world” (Rom. 4: 13).” Anthony Buzzard, The Coming Kingdom of the Messiah: A Solution to the Riddle of the New Testament