Fact will be stacked upon fact and scripture upon scripture in order to give you every advantage for understanding why each conclusion is drawn as it is. Please be aware that this type of study requires an unhurried and carefully thought-out approach to get at the core—the “trunk of the tree”—of the arguments and the conclusions drawn. Why? I want you to walk away from this study understanding God’s revelation in a way that you might never have understood it before. I want it to make a profound, life-changing impression upon your heart and mind that you have come in touch with knowledge from God to which you might not heretofore have been privy...that you have understood God’s truth and increased your faith in it. God reveals His truth and makes it clear to those who deeply desire to worship Him in spirit and in truth! Please consider the following example.
What Kind of “Gospel” Did Jesus Preach and Teach?
After His baptism and the temptation by Satan in the wilderness (Matt. 3:1-4:11), Jesus took up His role as an evangelist (an individual who brings God’s “good news” to others). In numerous places in the four “gospels,” Jesus makes it plain that He represents the Father, speaks the things the Father has sent Him to speak, and does the works the Father has commissioned Him to perform. So, His teachings and His works represent the “proof” that the Kingdom exists and that its power among mankind is demonstrated in order to turn them away from being unholy, blamable, and unloving so that they can, in fact, gain entrance into the future Kingdom (Matt. 12:28; Luke 10:9; Mark 12:28-34). That Kingdom power working among humankind is merely a sample of what shall be when the Kingdom is fully in power among mankind. It does not belong to flesh-and-blood (John 3:3; 1 Cor. 15:50).
Matthew 4:17 says: “From that time [after His baptism and temptation by Satan] Jesus began to preach, and to say, Repent [that is, change your life from being in opposition to God’s plan and will]: for the Kingdom of heaven is at hand.” Mark 1:14, 15 explains the same thing … except Mark calls it the Kingdom of God. There is no difference between the two. Matthew is not suggesting that the “gospel” is about going to heaven when you die. BAG points out that the Greek expressions basileia tou theou (kingdom of God) and basileia ton ouranon (kingdom of heaven):
…Have essentially the same mng., since the Jews used ouranos (-oi) as well as other circumlocutions [that is, expressions used to avoid saying the name of God; ex. = Adonai] for theos (Mt 19:23[, 24]…) … the latter term [ouranon] may also emphasize the heavenly origin and nature of the kgdm…. (BAG; p. 134).
That being said, Matthew and Mark are talking about the same thing. In Mark’s comments in v. 15, he quotes Jesus as saying that the gospel of the Kingdom of God is something to be believed. The Greek term from which this is translated is pisteuo, which has to do with the kind of belief/trust that emphasizes God’s power and nearness to help. It has to do with believing that God exists and that what He reveals to us is true (Ibid; pp. 666, 667). So, when Jesus Christ says “believe the gospel,” He is not making belief in the Kingdom of God optional. Nothing that God reveals to us through His Christ, His prophets, His Laws, et cetera is optional because it is all part and parcel to His truth (Isa. 8:20). This is the meaning behind John 4:23, 24; 8:31, 32; and 17:17. You are not free to pick and choose the parts of God’s truth that you like and neglect/ignore other parts that you do not like.
To mark the importance of the Kingdom on the earth concept in what Jesus taught and preached, please be reminded that it was He who taught us to pray to the Father: “Your Kingdom come. Your will be done in earth, as it is in heaven” (Matt. 6:10, 13; emphases added) … as well as: “Seek first the Kingdom of God, and His righteousness” (Matt. 6:33; emphases added). Wherever you find mention of God’s Kingdom in scripture, there you have witnesses that this Kingdom on the earth is what you are to believe in and to which you are to look forward. What do you think is the point of Zechariah 14:9 and Revelation 5:10? If it is not allowed for humans (flesh-and-blood) to inherit the Kingdom of God, would you agree that they would have to have a special bodily composition in order to do so (see 1 Cor. 15:51-54)?
It would make sense, then, that the “gospel of Christ” has as much to do with the gospel He preached and taught as it would with Him as a personage. In other words, the “gospel of the Kingdom” is about the Kingdom that God wills to be established on the earth by Jesus Christ. That is why Jesus was given all power in heaven and on earth.