The mystery which has 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. (Col. 1:26-27)
In NT times, a, “mystery,” was exactly what Paul describes here: A Truth previously hidden, but which is NOW revealed. According to Paul, the great mystery of previous ages and generations, which was THEN being revealed was, “CHRIST IN YOU, the hope of glory.”
Paul directly states that this Truth was, “hid from ages and generations,” past. Sure. Jesus Christ did not, and could not, dwell in anyone until after He completed His redemptive work, and ascended to the Father. Jesus said so – He said, “The Comforter has been WITH you, but SHALL BE IN YOU. I must go, for the Spirit cannot be descend down from heaven UNTIL I ascend up to heaven.” (see John 14:17 and 16:7)
Jesus Christ dwells in us through His Spirit — the Spirit of God. We are not indwelt by TWO spirits — but ONE. If you read this passage, and if you read Romans 8:9, you will see that Jesus Christ is in us via the spirit.
Contrary to some Christian teaching, Jesus Christ came to dwell in people for the very first time in Acts 2 when His Spirit did descend. Acts 2 began the New Covenant – which IS CHRIST in you. Acts 2 began the church – which consists of those in whom Christ dwells. The day of Pentecost was fulfilled in Acts 2 — and the mystery unveiled.
In the church today, we have made the church age the age of the Holy Spirit. This is off center, and has led to much error. The very purpose for which the Spirit of God was given — the purpose which Jesus stated in John, chapters 14 thru 16, and which is taught all through the epistles — is to reveal Christ TO us, IN us, and THROUGH us. Indeed, so that we would not misunderstand, Jesus even stated that the Spirit of God would never speak about the Spirit of God — that is, the work of the Spirit would never result in a focus upon the Spirit. The Spirit of God would absolutely always focus upon the Person of Jesus Christ — the Spirit of God would bring us into an inner realization of the Person of Jesus Christ.
The number one indication that the Spirit of God is working in my life is that I am becoming more and more preoccupied with the Person of Jesus Christ. I am losing my life — and Jesus is becoming my life. This is what it really means to be guided into all Truth. It is Christ in us, the hope of glory — not merely as a theological concept — but as a living experience of the Person whom has come to dwell within us.