It all depends on how one defines words, of course, but the word “religion” is a low standard word. Religion is the attempt to achieve righteousness through keeping a set of rules (impossible the Bible says very clearly). Jesus called the religious Pharisees “snakes” and “pit vipers.”
Jesus is the door (through His blood). This is the gospel. This is the gospel (death, burial and resurrection–where He was the sole person involved: priest who offered Himself, the sacrificial lamb and the One who shed blood). The gospel is defined at 1 Corinthians 15:1-4. Jesus is the Savior with respect to the gospel. The gospel is the blood in the basin during the Passover.
The gospel of the kingdom is not the same as the gospel. Jesus is the King with respect to the gospel of the Kingdom. Jesus as shepherd, leading His sheep through the Holy Spirit, is the gospel of the Kingdom. After He arose He said, “I am the resurrection and the life” (through Me you may have spiritual breath from the Father). The gospel was an event, both in time and eternity–His literal death as fully man and fully God–involving His death, burial and resurrection. But then after He arose He (not an event) became the resurrection–as a person. He—a Person, not an event–is the resurrection.
We cannot earn righteousness. Through faith in the resurrection of Christ on our behalf and in our place we receive imputed righteousness. This is the gospel. But we do work, not to be made righteous, but to be made holy (sanctification) due to the motivation from love to obey His commands. 2 John 6. Sanctification involves hard work. This is the gospel of the Kingdom. This is the denying self [in Greek, killing the soul (Greek word is aparneomal–killing)–the intellect, the will and the emotions [the self], taking up our cross and following Him. That is hard work! It does not make us righteous (I am no more righteous than Hitler). But due to what Christ did on the cross (the gospel), which allows me to appropriate the free gift of grace through faith, I will be (daily) killing the desires of the soul [Mark 8:35; Luke says daily], putting to death the deeds of the body [Romans 8:13], warring against Satan in the mind [2 Corinthians 10:3-5]. The blood of Jesus represents death; His resurrection represents life–death and life are not the same. His blood is the gospel; His resurrection is the gospel of the Kingdom (I am the way, the truth and the life and no one comes to the Father except by Me).
The gospel is our going into Christ. By faith we receive grace and imputed righteousness. This is our going into Christ (the big cross of Moses in the Tabernacle).
The hidden mystery of the ages is Christ in you (the gospel of the Kingdom—which is not you in Christ, the gospel). Colossians 1:26-27. “Even the mystery which hath been hid from ages and from generations, but now is made manifest to his saints: To whom God would make known what is the riches of the glory of this mystery among the Gentiles; which is Christ in you, the hope of glory:”
Please note that God willed to make known this mystery: Christ in you.
The gospel of the Kingdom is Christ coming into us. It is not our going into Christ. This is the Christian life (following the Way–Jesus). This is the little cross of Moses (in the Tabernacle). This is the water (sanctification–I did not come by water only, but by blood and water). Only by killing the desires of the I/ego [the soul], putting to death the desires of the body [desires of the five senses], and warring against Satan in the mind, do we make room for Christ. This is Christ coming into us. Our going into Christ and Christ coming into us are not the same. But both are required (blood and water–washed by the water of the Word–sanctification). Obedience (the motivation is from love of what Christ did for us–2 John 6), is the ONLY source of eternal salvation. Hebrews 5:9. And Christ comes back to get only those who belong to Him. And who are they? Those who belong to Christ are crucifying [Greek is always written in the active voice regarding what we must be doing] the fleshly nature (desires of the soul and body) with its passions and desires. Galatians 5:24. Those who are going through sanctification (not to be made righteous, because faith in Christ’s resurrection on our behalf can make us righteous) are following after Christ—becoming more like Him (sanctification). “…If anyone would come after Me, he must deny himself [deny his soul—the will, intellect and the emotions] and take up his cross daily and follow Me.” Luke 9:23. We are made righteous (imputed righteousness) through faith in the resurrection of Christ; however, due to our love of Christ, we want to become more holy. “Make every effort to live in peace with all men and to be holy [sanctification]; without holiness no one will see the Lord.” Hebrews 12:14. Becoming holy (following after Christ) is the out workings of righteousness.
So, the desires of the soul must be killed (and Jesus gave us the power to be killing the desires of the soul through His death–Romans 4:25) so that we can have breath (spirit) and life (spirit) from the Father. So, we do not better the soul, we kill it (desires). By killing the desires of the soul, we make room for Christ and His and His Father’s spirit to come into us.
By definition (in Greek) the soul is the I/ego. It sees things of time (this age) as important. By definition, the body (in Greek) consists of the five senses. The five senses see the things of this world as important. World (cosmos, in Greek) means the social order established by humans that does not recognize God as sovereign. The world tells our five senses what is important. The soul sees things from the selfish I/ego as important. The Bible says to kill these desires (Christ coming into us–the gospel of the Kingdom, the following of Christ, sanctification and being washed and cleansed by the water of the Word). We are to replace the desires of the soul as follows:
I think, I rationalize are replaced by God’s Word;
I will is replaced by God’s will; and
I feel is replaced by God’s standards.
We must be doing this every day.
It is important not to argue religion and be concerned or focused on church doctrines and their potential judgmental, rules. It is important to stay in the Word, not church doctrine. The only rules of the New Testament are to love God with all our hearts, souls and minds, and our neighbors as ourselves. If we do this, we need no rules.
Matthew 24:14: “And this gospel of the Kingdom will be preached in the whole world as a testimony to all nations, and then the end will come.” This is Jesus’ response to the disciples when they asked Him when the world would come to an end. Notice that Jesus did not say this “gospel” will be preached to the whole world; He said this “gospel of the Kingdom” will be preached. The gospel is the death, burial and resurrection of Christ. 1 Corinthians 15:1-5. This is the gospel, but it is not the gospel of the Kingdom.
Matthew is the gospel of the King. Mark is the gospel of the servant. Luke is the gospel of Jesus as a human being. And John is the gospel of Jesus as the Son of God.
Matthew 4:23-24 are the first verses in the Bible about the gospel of the Kingdom of God.
The Kingdom of God is always attested by a demonstration of power. This demonstration is always in healing the sick and casting out demons (evil spirits).