The word “mystery” appears, in some form, 27 times in the KJV New Testament.  Some might wonder, if the Bible is a “mystery” can anyone understand it?  I believe this misses how this word is commonly used in the New Testament.  Let us notice…

1.  The word is used to refer to something(s) in God’s scheme of redemption and plan for man, which was once unknown to man in times past, or at least not clearly or fully revealed to man.  However, now God has revealed such through inspiration.  Romans 16:25-26: “Now to Him who is able to establish you according to My gospel and the preaching of Jesus Christ, according to the revelation of the mystery kept secret since the word began but now made manifest, by the prophetic scriptures made known to all nations…”  Ephesians 2:18, 20; 3:3-5: “For through Him we both have access by one Spirit to the Father… having been built on the foundation of the apostles and prophets, Jesus Christ Himself being the chief cornerstone… by revelation He made known to me the mystery… by which when you read, you may understand… which in other ages was now made known to the sons of men, as it is now revealed by the Spirit to His holy apostles and prophets.”  Colossians 1:26: “The mystery which has been hidden from ages and from generations… now has been revealed to His saints.”  They mystery was revealed in the first century by inspired men.  Thus, the “mystery” is no longer a “mystery.”

2.   The mystery concerns the redemptive work of Christ.  1 Timothy 3:16: “And without controversy great is the mystery of godliness: God was manifested in the flesh, justified in the Spirit,  seen by angels, preached among the Gentiles, believed on in the world, received up into glory.”

It is true that there were hints of God coming in the flesh (Isaiah 9:6-7; 40:3; Micah 5:2) and hints of the Messiah’s death and resurrection (Psalm 22; Isaiah 53, etc.).  however, such was not clearly revealed or understood (Isaiah 53 cf. Acts 8:30-35).

3.  The mystery concerns the location of salvation.  Ephesians 1:7-10: “In Him, we have redemption through His blood, the forgiveness of sins… having made known to us the mystery of His will… that in the dispensation of the fullness of the times, He might gather together in one all things in Christ, both which are in heaven and which are on earth – in Him.”  The words “gather together” literally means, “to head up.”  The words “in one” are supplied.  Christ has received “all authority… in heaven and on earth” (Matthew 28:18), and “in Him” is redemption.

4.  The mystery concerns the inclusion of the Gentiles.  Ephesians 3:3-6: “How that by revelation He made known to me the mystery… that the Gentiles should be fellow heirs, of the same body, and partakers of His promise in Christ through the Gospel.”

It is true that there were hints (Genesis 12:3; Isaiah 2:2; 62:1-2).  However, this was not clearly understood by either the Jews or the Gentiles.  It took Divine intervention to bring Jew and Gentile together (Acts 10-11).

 5.  The mystery concerns the relationship between Christ and the church.  Ephesians 5:22-32: “Wives, submit to your own husbands, as to the Lord.  For the husband is the head of the wife, as also Christ is the head of the church… Husbands, love your wives, just as Christ also loved the church and gave Himself for her… ‘For this reason a man shall leave his father and mother and be joined to his wife, and the two shall be one flesh.’  This is a great mystery, but a speak concerning Christ and the church.”

Think of these parallels: (a) Both Adam and Jesus had their sides opened to receive their brides (Genesis 2:21-22 cf. John 19:34).  (b) Both received only one bride [Genesis 2 cf. Ephesians 4:4 (one body) cf. Ephesians 1:22-23 (the body is the church)].  (c) There is closeness (Genesis 2:23-24 cf. Ephesians 5:30-32).  (d) There is to be fidelity (Hebrews 13:4 cf. 2 Corinthians 11:2; James 4:4).  (e) The wife is to be submissive (Ephesians 5:22-23).  (f) The husband is to love his wife (Ephesians 5:25).  Christ “loved the church and gave Himself for her.”

The mystery has been revealed.  It is according to God “will,” “purpose,” “eternal purpose” (Ephesians 1:9; 1:11; 3:11).  It has always been God’s plan, and now His plan is revealed.