Paul tells us Israel “stumbled” as they opposed Jesus and called for Him to be crucified. (Rom. 9:32, 11:11). Then Israel did “fall” when they stoned Stephen to death in Acts 7. Thus, Israel and its prophetic program was set aside “until the fulness of the Gentiles be come in.” With this, Israel is set aside until “the body of Christ” is completed with the last member being added to “the [Gentile] body of Christ.”

“For I would not, brethren, that ye should be ignorant of this mystery, lest ye should be wise in your own conceits; that blindness in part is happened to Israel, until the fulness of the Gentiles be come in.” (Rom. 11:25)

The “mystery / secret” revealed to Paul was this; that God would create a new “pure grace” dispensational program, to save Gentiles totally APART from fallen Israel and her Law program, and Apart from Israel’s coming Kingdom; and that the riches of salvation would come to Gentiles through Israel’s ‘FALL.’

“…  Through Their (Israel’s) FALL Salvation Is Come Unto The Gentiles, for to provoke them (Israel) to jealousy. ¹²…if the FALL of them [Israel] be the Riches of the world, and the Diminishing of them [Israel] the Riches of the Gentiles; how much more their fulness? ¹³For I (Paul) speak to you Gentiles, inasmuch as I am THE apostle of the Gentiles, I magnify [honor] mine (Christ-given) office:” (Rom. 11:11b-13)

It was revealed to Paul that, through Jesus Christ’s finished crosswork, salvation would go to “all nations (Gk. ethnos, Gentiles and Jews),” that salvation would reach ALL nations without Israel being converted.

Through Paul we learn of “The mystery which hath been hid from ages and from generations, but now is made manifest to his saints (believers)” (Col. 1:26). Stated once more, this “mystery” that was “hid” consists of the details of the secreted program of God that were first revealed to the Apostle Paul as seen in his thirteen epistles (Romans through Philemon).

Bible teachers and students rarely understand Paul’s unique ministry. They don’t understand what was “hid” and “is now made manifest” (v26), so they stumble over Col. 1:27. God wanted to make known something to us; verses 25-27 explain what that something is. God wants us to understand the Mystery Program, and understand “The Riches of the glory of this mystery among the Gentiles.”

Jesus Christ; crucified and in His resurrected fulness as He now is… brings into us “the riches of the glory (the full expression) of this mystery” that Paul reveals to us in his epistles.

Paul’s prayer for the Ephesians elaborates upon these “riches” and helps us define the importance and worth of “the mystery” for believers. Notice that Paul prays for their ‘wisdom and revelation’ “in the knowledge of HIM.” Then for their understanding, enlightenment concerning the hope of their calling and “the riches of the glory of his inheritance IN the saints” and accordingly, “His power to us-ward who believe,”

“That the God of our Lord Jesus Christ, the Father of glory, may give unto you the spirit of wisdom and revelation in the knowledge of him: ¹⁸The eyes of your understanding being enlightened; that ye may know what is the hope of his calling, and what the riches of the glory of his inheritance IN the saints, ¹⁹And what is the exceeding greatness of his power to us-ward who believe, according to the working of his mighty power, ²⁰Which he wrought in Christ, when he raised him from the dead, and set him at his own right hand in the heavenly places, (Eph 1:17-20)

It’s clear that from the verses above that Paul is saying we need to “know” “the RICHES of The Glory of His Inheritance IN the Saints” (v18). These “riches” clearly define “this mystery” seen here in Col. 1:27. 

“To whom God would make known what is the riches of the glory (full expression) of this mystery among the Gentiles; which is Christ in you, the hope of glory: (Colossians 1:27 (KJV)  

The “mystery” explains the indwelling Christ and includes… all the doctrinal details, the special information, that the ascended Lord Jesus disclosed to the Apostle Paul. This is the doctrine that the Holy Spirit revealed to Paul “for ye Gentiles” (Eph. 3:1) … via Paul’s un-prophesied Apostleship and ministry. This information is the truth that makes us saved, secure and supplied by all that Christ has done for us at the cross and all that He now is by His “Spirit of life” now living in every grace age believer. It also includes the joint-body consisting of Jews and Gentiles without distinction in the one “body of Christ” of today’s grace age.

We learn about “Jesus Christ according to the revelation of the mystery,” (Rom 16:25) by reading Paul’s epistles (Eph. 3:4; 2 Tim. 2:7). Most Christians will say “I know about Jesus,” but to really know Him. We can know Christ know in the light of the details of “the revelation of the mystery” that reveal all that His sacrificial death has done for us and… that His resurrection life is in us!

“Whereby, when ye read, ye may understand my knowledge in the mystery of Christ)” Eph. 3:4 (KJV)
“Consider what I say; and the Lord give thee understanding in all things.” 2 Tim. 2:7 (KJV)