Dr. Couch, what is the gospel of the kingdom mentioned in Matthew 24:14?
Answer: It is the "good news" about the coming kingdom of Christ that would be preached during the terrible period of the tribulation. We know this by the context of 24:4-28. This is not what the apostles were proclaiming. While the tribulation is bad, it will be the most productive period of evangelism ever! The gospel of the kingdom is about the fact that the Messiah is both the Savior and the coming King. Salvation is embedded in that message but the focus is about the fact that His coming will counter the kingdom of the antiChrist. Note that the gospel of the kingdom will be preached "for a witness to all the nations and then the end shall come" (Matt. 24:14). This may not happen now because the dispensation of the church age could end at any time be the rapture of the church!
We know from Acts that the disciples were proclaiming the gospel of personal salvation. See Acts 15 and look at what was happening at the Jerusalem Council. "Conversion of the Gentiles" (v. 3) and the fact that the Jews, the Pharisees, were believing in Christ as their Savior (v. 5). The Jews and the Gentiles were having their hearts "cleansed by faith" (v. 9). "Signs and wonders were being performed among the Gentiles" (v. 12). But after this, someday the Lord would return "and rebuild the tabernacle of David which had fallen," i.e. the kingdom (v. 16).
This coming kingdom would be announced during the tribulation as the "gospel of the kingdom" mentioned in Matthew.
Thanks for asking.
—Dr. Mal Couch (2/11)