We read what both John the baptizer and Jesus preached.

Mt. 3:1-2: “In those days John the Baptist came preaching in the wilderness of Judea, and saying, 'Repent, for the kingdom of heaven is at hand.”’ Jesus’ message was no different: Mt. 4:17, “From that time Jesus began to preach and to say, 'Repent, for the kingdom of heaven is at hand.'“ After John was put in jail Jesus said in Mk. 1:15, “The time is fulfilled, and the kingdom of God is at hand. Repent, and believe in the gospel.” Jesus stated in Mt. 9:13, “For I did not come to call the righteous, but sinners, to repentance.” (Also Mk. 2:17.)

The gospel of the kingdom (Mt. 4:23; 9:35; 24:14; Mk. 1:14) is the declaration in which Jesus Christ is to set up His kingdom on earth and is to be physically present to rule.

The kingdom was offered to Israel the first time Jesus came physically to earth, as a nation they rejected it, (Mt.12) because they rejected the king of this kingdom (this is not a permanent rejection). The kingdom was withdrawn from being established (as was prophesied in Scripture). Jesus had to die first. It is the gospel that brings one to be in the kingdom and enjoy the benefits (which are not all available now).

Paul writes in Rom. 14:17 “for the kingdom of God is not eating and drinking, but righteousness and peace and joy in the Holy Spirit.” These are available to every believer now, they are a foretaste of the kingdom to come. 1 Cor. 4:20: “For the kingdom of God is not in word but in power.” The Holy Spirit is given to the individual and transforms their lives, it is process.

The kingdom is different than the gospel (Acts 1:6-7). We later see this distinction made. It is the kingdom that is declared through the gospel that saves (Acts 19:8).

Jesus in Mt. 4:23 was “preaching the gospel of the kingdom.” There are various descriptions of the different facets of the gospel that are all about Christ, the person and His work on the cross as the message by the apostles. The Gospel of God - Rom. 1:1; 15:16; 2 Cor. 11:7; 1 Thess. 2:2,8,9; 1 Pet. 4:17. God’s plan; God initiating the solution to sin by sending His Son to die for our sins.

The gospel of Jesus Christ (Mk 1:1) was proclaiming the Son of God and the accompanying kingdom in the gospel accounts.

The gospel of the grace of God - Acts 20:24 is the message of unmerited favor, God’s mercy toward sinful man in the gospel that brings salvation, peace to both Jews and Gentiles by the new covenant (Acts 15:11; 1Cor. 1:4; 2 Cor. 6:1-2; Gal.1:6; Titus 2:11).

At the last supper Jesus explains the significance of the Passover they had been keeping for 1500 years. Lk. 22:14- 20: “When the hour had come, He sat down, and the twelve apostles with Him. Then He said to them, “With fervent desire I have desired to eat this Passover with you before I suffer; for I say to you, I will no longer eat of it until it is fulfilled in the kingdom of God.” So He is teaching the kingdom is not yet – it is future. Spiritually, we are in the kingdom by being born again and the kingdom is in us (via the Holy Spirit) but physically it is yet to come.

Mt. 26:27-28: Then He (Jesus) took the cup, and gave thanks, and gave it to them, saying, “Drink from it, all of you. For this is My blood of the new covenant, which is shed for many for the remission of sins.”

After the resurrection Jesus commissioned his followers. Mark 16:15-16: And He said to them, “Go into all the world and preach the gospel to every creature.” Which is what the bread and the cup were about, His physical death for our sins.

The gospel is preached and it is heard to bring faith… What is the message? 1 Cor.1: 18: it is “the message of the cross’ that is the power of God to SAVE - Through faith! “By grace you have been saved through FAITH” (Eph.2:8). The message was the same to both the Jews and the Gentiles. Acts 20:21: “repentance toward God and faith toward our Lord Jesus Christ.”

Acts 8:2: “So when they had testified and preached the word of the Lord, they returned to Jerusalem, preaching the gospel.” Rom. 1:15: Paul stated “I am ready to preach the gospel.”

1 Cor. 1:17-18: “For Christ did not send me to baptize,” “but to preach the gospel, not with wisdom of words, lest the cross of Christ should be made of no effect.” “For The message of the cross is foolishness to those who are perishing, but to those who are being saved it is the power of God.”

“For I am not ashamed of the gospel of Christ, for it is the power of God to salvation for everyone who believes” (Rom. 1:16).

There is no forgiveness without the blood of Christ, nor can one enter the kingdom without forgiveness and the new birth.

All throughout the book of Acts the apostles preached on His person and His work. Christ is the center piece of the gospel, it is based on his work four our salvation.

Acts 2:23-24: “Him, being delivered by the determinate counsel and foreknowledge of God, ye have taken, and by wicked hands have crucified and slain: Whom God hath raised up, having loosed the pains of death.”

Acts 4:2: “they taught the people and preached in Jesus the resurrection from the dead.”

Acts 4:10-12: “Be it known unto you all, and to all the people of Israel, that by the name of Jesus Christ of Nazareth, whom ye crucified, whom God raised from the dead even by him doth this man stand here before you whole. This is the stone which was rejected by you builders, which is become the chief cornerstone. Neither is there salvation in any other: for there is no other name under heaven given among men, whereby we must be saved.”

(The Apostles) Acts 5, “They did not cease preaching and teaching that Jesus is the Christ”

Acts 8:5 “Then Philip went down to the city of Samaria and preached Christ to them.”

Acts 9:20: Immediately after Paul’s conversion he “Preached Christ in the synagogues that he is the SON OF GOD.” vs. 22 proving Jesus is the Christ. V.42 many believed on the Lord (Jesus).

Acts 10:36: Peter preached peace through Jesus Christ- “he is LORD OF ALL.”

Acts 10:43: “Through his name whoever believes in him will receive forgiveness of sins.”

Acts 11:20: Barnabas and Paul Preached Jesus. Continually we find their message centers on His work and His personhood.

Acts 13:33-39: The death and resurrection are preached v.38 “through this man is preached the forgiveness of sins.”

Acts 14:1-3: “It was by the word of grace that many believed.”     

Acts 15:7 “that by my mouth the Gentiles should hear the word of the gospel and believe.”

Acts 17:2-3: “he preached to them Jesus and the resurrection.” The gospel centers on the person and work of Jesus (Rom. 4:16; 5:2)

They preached Jesus’ crucifixion, his person and the work he did by crucifixion.

1 Cor. 2:2 says, “For I determined not to know anything among you except Jesus Christ and Him crucified.”

Acts 19:8: “And he (Paul) went into the synagogue and spoke boldly for three months, reasoning and persuading concerning the things of the kingdom of God.” That would be the things pertaining to Christ.

After Jesus resurrected this is what he told the disciples:

Mark 16:15-16: And He said to them, “Go into all the world and preach the gospel to every creature.

After He resurrected they asked Him, saying, "Lord, will You at this time restore the kingdom to Israel?" And He said to them, "It is not for you to know times or seasons which the Father has put in His own authority” (Acts 1:6-7)

The kingdom is yet to come on earth. The kingdom is declared through the gospel that saves:

Heb. 6:4-5 “For it is impossible for those who were once enlightened, and have tasted the heavenly gift, and have become partakers of the Holy Spirit, and have tasted the good word of God and the powers of the age to come, (referring to the literal kingdom)

2 Tim. 4:1: “I charge you therefore before God and the Lord Jesus Christ, who will judge the living and the dead at His appearing and His kingdom”

Jesus Christ must return to establish His authority and rule on earth for His kingdom to officially commence. To do this He separates the sheep from the goats (Mt.25), removes those who do evil and came against his people. Then the faithful church will rule and reign under his leadership which will be centered in Jerusalem.