Col 1:3-14 We always thank God, the Father of our Lord Jesus Christ, when we pray for you, since we heard of your faith in Christ Jesus and of the love that you have for all the saints, because of the hope laid up for you in heaven. Of this you have heard before in the word of the truth, the gospel, which has come to you, as indeed in the whole world it is bearing fruit and growing—as it also does among you, since the day you heard it and understood the grace of God in truth, just as you learned it from Epaphras our beloved fellow servant. He is a faithful minister of Christ on your behalf and has made known to us your love in the Spirit. And so, from the day we heard, we have not ceased to pray for you, asking that you may be filled with the knowledge of his will in all spiritual wisdom and understanding, so as to walk in a manner worthy of the Lord, fully pleasing to him, bearing fruit in every good work and increasing in the knowledge of God. May you be strengthened with all power, according to his glorious might, for all endurance and patience with joy, giving thanks to the Father, who has qualified you to share in the inheritance of the saints in light. He has delivered us from the domain of darkness and transferred us to the kingdom of his beloved Son, in whom we have redemption, the forgiveness of sins.
Early as a Christian, I was told that the gospel is about life after death. But as I begin to do Alpha and read the Gospels carefully, I found that Jesus was preaching "another" gospel--it's called the Gospel of the Kingdom of God. The "kingdom of God" (or "kingdom of heaven" in Matthew) was not just something we go to after we die. Rather the kingdom of God is something that has arrived--and has, in fact, come: "But if it is by the Spirit of God that I cast out demons, then the kingdom of God has come upon you" (Matt 12:28). The Gospel is good news--not for the dead and dying, but for the young and living. While it's true that the perfect expression of the Kingdom of God will only come when Jesus returns, nevertheless, it is already here -- since the Day of Pentecost, when the Spirit descended upon the church as recorded in Acts 2:1-4.
So when a person puts his or her trust in Christ and confesses Him as his or her Lord, that person is "delivered...from the domain of darkness and transferred...to the kingdom of his beloved Son" (v.13). Note that Paul states that God has delivered and transferred us from Satan's kingdom into Christ's kingdom. It's perfect present tense, which means that it was something that has already happened and its effect is being felt today. What's the implication? It means that salvation is not just about the afterlife but about this life. Salvation is not life after death, but life before and beyond death.
Once we have been transferred into Christ's kingdom, "we have redemption, the forgiveness of sins" (v.14). In other words, we have been forgiven and with that comes the gift of the Spirit: "Repent and be baptized every one of you in the name of Jesus Christ for the forgiveness of your sins, and you will receive the gift of the Holy Spirit" (Acts 2:38). Once we are transferred into Christ's kingdom, we inherited all the spiritual blessings that are part of this Kingdom, viz., the forgiveness of our sins and the gift of the Holy Spirit. It also includes the restoration to wholeness our diseased and dying spirit, soul and body. We experience God's life infusing our entire being, bringing a new sense of joy and freedom that we have never experienced before.
But for this to happen, as in any kingdom, we need to acknowledge and submit to the new King and live by His law (OS). The kingdom of light is more than just an upgrade of the kingdom of darkness--it's an entirely new OS. Its operational power is different (Spirit, not self) and its operational rules are also different (law of Christ, not law of Moses or conscience). And we become members of this new kingdom through repentance and water baptism. Those who opt not to be baptized are opting out of this new Kingdom OS where there is forgiveness of sins, power of the Spirit and the healing of the whole person.
This is the Gospel of the Kingdom--the good news that God's kingdom has arrived and anyone who puts his or her trust in Christ and acknowledges Him as the Lord and King can have access to all the kingdom blessings today. While the blessings are only partial, not perfect, they are as good as can be for this life: "For we know in part and we prophesy in part, but when the perfect comes, the partial will pass away" (1 Cor 13:9-10).