The early apostles and Christians. The early apostles and Christians of the Christian Era preached and taught the Kingdom of God: the Kingdom prophesied in the Old Testament; the Kingdom proclaimed by John the Baptist and by the Lord Jesus; the Kingdom beheld in vision by the Apostle John:

But when they believed Philip preaching the things concerning the kingdom of God, and the name of Jesus Christ, they were baptized, both men and women. (Acts 8:12)

"Things concerning the kingdom of God."

Confirming the souls of the disciples, and exhorting them to continue in the faith, and that we must through much tribulation enter the kingdom of God. (Acts 14:22)

"Enter the kingdom of God."

And he went into the synagogue, and spake boldly for the SPACE of three months, disputing and persuading the things concerning the kingdom of God. (Acts 19:8)

"Things concerning the kingdom of God."

And Paul dwelt two whole years in his own hired house, and received all that came in unto him, Preaching the kingdom of God, and teaching those things that concern the Lord Jesus Christ, with all confidence, no man forbidding him. (Acts 28:30,31)

"Preaching the kingdom of God." The writer of the Book of Hebrews agrees:

Wherefore we receiving a kingdom that cannot be moved, let us have grace, whereby we may serve God acceptably with reverence and godly fear: (Hebrews 12:28)

"Receiving a kingdom." And James, the Lord's brother:

Hearken, my beloved brethren, Hath not God chosen the poor of this world rich in faith, and heirs of the kingdom which he hath promised to them that love him? (James 2:5)

"Heirs of the Kingdom." Peter preached not only the gift of God's grace but also the need to press into the kingdom of God:

Wherefore the rather, brethren, give diligence to make your calling and election sure: for if ye do these things, ye shall never fall: For so an entrance shall be ministered unto you abundantly into the everlasting kingdom of our Lord and Saviour Jesus Christ. (II Peter 1:11)

"The everlasting kingdom." The Apostle John associated the Kingdom of God with tribulation and patience:

I John, who also am your brother, and companion in tribulation, and in the kingdom and patience of Jesus Christ, was in the isle that is called Patmos, for the word of God, and for the testimony of Jesus Christ. (Revelation 1:9)

"In the kingdom." This reminds us of the exhortation of Paul: "We must through much tribulation enter the kingdom of God."

John heard the seventh angel announce the coming of the life of Heaven into the nations of the earth:

And the seventh angel sounded; and there were great voices in heaven, saying, The kingdoms of this world are become the kingdoms of our Lord, and of his Christ; and he shall reign for ever and ever. (Revelation 11:15)

"The kingdoms of our Lord." The words the kingdoms, after the word "become," are not in the original text. The original text gives us a better flavor of the Kingdom of God:

"The kingdom of the world has become of our Lord, and of his Christ."

Here is the passing of the material realm into the hands of God in Christ in the saints. This is the point at which the "one like the Son of man" was given "dominion, and glory, and a kingdom, that all people, nations, and languages, should serve him." This is the coming of the Kingdom of God announced by John the Baptist, Jesus of Nazareth, and the Apostles of the Lamb. (from The Kingdom of God)