The Mystery Doctrines
THE MYSTERY TEACHINGS ARE ALL FOR THE CHURCH.  They were unknown in the Old Testament.  Isaiah, Jeremiah and David knew nothing of this revelation.   This is New Testament teaching only, for the Church.   The teaching on “mystery”  means there is a group of people called “the Church”, which started at the day of Pentecost, and will end at the Rapture of the Church.  The Church-Age was unknown in the Old Testament.   It was a mystery.   Even in Acts 1, the disciples asked: When’s the (Messianic) Kingdom coming?

THE MYSTERY DOES NOT INCLUDE :
[1] The Death  of Christ
[2] His Burial
[3] His Resurrection
[4] His Ascension
[5] His Sitting at the right hand of the Father
[6] The Tribulation
[7] The Second Advent
[8] The Millennium
ALL THESE ARE WELL-DOCUMENTED IN THE OLD TESTAMENT AND OCCURRED BEFORE THE DAY OF PENTECOST.

THE MINISTRY OF THE APOSTLES (especially Paul) was to reveal the fullness of the Mystery.
I rejoice in my sufferings for you, and fill up that which is behind of the afflictions of Christ in my flesh for his body's sake, which is the church:  whereof I am made a minister, according to the stewardship of God which is given to me for you, to fulfil (bring to completion) the Word of God (PAUL’S RESPONSIBILITY WAS TO COMPLETE THE WORD OF GOD by revealing the Mystery, i.e. what the Old Testament didn't reveal) even the MYSTERY which has been HID from ages and from generations, but now (in the Church-Age) is made manifest to His saints" (Colossians 1:24-26).    WE ARE THOSE SAINTS!   What a privilege!  THE MYSTERY TEACHINGS ARE  FOR THE CHURCH.

The Epistles in particular give the revelation of this mystery:
I will not be negligent to put you always in remembrance of these things, though you know them and be established IN THE PRESENT TRUTH (2 Peter 1:12).
By revelation he made known to me the MYSTERY... the MYSTERY OF CHRIST, which in other ages was not made known to the sons of men, as it is now revealed to his holy apostles and prophets by the Spirit; that the GENTILES should be FELLOW-HEIRS, and of the SAME BODY, and PARTAKERS of his promise IN CHRIST by the gospel (Ephesians 3:3-6).

Paul's ministry was: to make all men see what is the dispensation (time-period) of THE MYSTERY which from the beginning of the ages has been hidden in God (v9).    The heart of this Mystery was the formation of a NEW MAN, a New Creation, distinct from Israel - the BODY of Christ, in which Jew and Gentile would be equal.  All who believe in Christ are united to Him and He indwells them - CHRIST IS IN THEM and THEY ARE IN CHRIST.

To Him who is of power to establish you according to my gospel, and the preaching of Jesus Christ, according to the revelation of the MYSTERY, which was kept SECRET since the world began,  But now is made manifest, and by the scriptures of the prophets, according to the commandment of the everlasting God, made known to all nations for the obedience of faith (Romans 16:25,26).   So, a New Testament MYSTERY is a REVEALED SECRET,  truth that was unknown in the Old Testament, a secret hidden in God since the foundation of the world but now revealed to believers through Christ and His apostles.

Paul asked for prayer that utterance and boldness would be given him that he would be able: to make known the MYSTERY OF THE GOSPEL (Ephesians 6:19) or the MYSTERY OF CHRIST (Colossians 4:3).  When we pray in tongues, we speak out  the MYSTERIES of the faith and of our lives (1Corinthians 14:2).  See also Ephesians 1:9-11, Colossians 2:2,9; 4:3.

A BREAKDOWN OF THE MYSTERY- THE MYSTERY OF THE FAITH  (1Timothy 3:9).
The Faith = the body of New Testament revelation.

1. The Mystery of Godliness (1Timothy 3:16).
Without controversy great is the MYSTERY of godliness.
This concerns the  MANIFESTATION OF GOD'S ANOINTED IN HISTORY.
(1) God MANIFEST in the flesh.  THE IDENTITY OF THE CHRIST = JESUS OF NAZARETH.   This Mystery was revealed in the first seven years AD26-33.  Although the Old Testament prophesied the God-man, it remained for Him to be manifested and revealed to us what He is like. "For verily I say to you, that many prophets and righteous men have desired to SEE those things which ye see, and have not seen them; and to hear those things which ye hear, and have not heard them" (Matthew 13:17).
(2) Justified in the Spirit (the resurrection proved He is the One).
(3) Seen by angels (His triumphant ascension).

The first three concern Christ, the Head.
The next three concern Christ the Body:

(4) Preached among the Gentiles (see the Parable of the Sower).
(5) Believed on in the world (the formation of a new believing community of Jew and Gentile called 'Christ' - see ‘the Mustard Seed’).
(6) Received up into glory (the Rapture - see the Pearl).

This covers the revelation of the MESSIAH to man, from His incarnation to His ascension; and then also the formation of HIS BODY (the Church) from its birth to its ascension (the Rapture).  Thus, 1 Timothy 3:16 gives an overview of the whole Mystery Age. Alongside this is the working of the Mystery of Iniquity (2Thessalonians 2:7) growing through the same Age (1Timothy 4:1-5).   See the Wheat and Tares and the Leaven.

2.  The Blindness of Israel in this dispensation (Romans 11:15-27):
Romans 11:25:  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 fullness of the Gentiles be come in.
This mystery is that ISRAEL is blinded in unbelief and CUT OFF FOR THE CHURCH AGE for their REJECTION OF CHRIST (the Treasure hid in a field), for the purpose of God’s grace going out for the salvation of Gentiles in the Church-Age.  However the blindness is partial (some believe) and not final, for Israel will be grafted back in again after the Rapture.

3.  The Calling out and formation of the CHURCH.

   [1] The BODY of Christ (a new body of Jew and Gentile, distinct from Israel, formed on the basis of faith in Christ and joined spiritually to Him).
If ye have heard of the dispensation of the grace of God which is given me for you.   How that by revelation he made known to me the MYSTERY; (as I wrote before in few words - Ephesians 2 -   whereby, when you read, you may understand my knowledge in the MYSTERY OF CHRIST), which in other ages was not made known to the sons of men, as it is now revealed to His holy apostles and prophets by the Spirit; that the GENTILES should be FELLOW HEIRS, and of the SAME BODY, and PARTAKERS of His promise IN CHRIST by the gospel (Ephesians 3:2-6, see also Ephesians 2:11-22).   The Church is a NEW MAN (made from Jew and Gentile) not a continuation of Israel (Ephesians 2:15).   This BODY is called CHRIST (1Cor 12:12).

   [2] The BRIDE of Christ:
Husbands love your wives as Christ loved the Church and gave Himself for it ...that He might present it to himself a glorious Church, not having spot, or wrinkle, or any such thing; but that it should be holy and without blemish...we are members of His body, of His flesh and of His bones, ..for 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 I speak concerning CHRIST and THE CHURCH (Ephesians 5:25-32).

  [3]  The CHURCH as God's anointed WITNESS:
The MYSTERY of the seven stars which you saw in my right hand, and the seven golden- candlesticks.  The seven stars are the messengers of the seven churches: and the seven candlesticks which you saw are the seven churches (Revelation 1:20).

  [4] The INDWELLING of Christ.
Even 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 (Colossians 1:26, 27).

  (5) WHO WE ARE IN CHRIST:
We speak the wisdom of God in a MYSTERY, even the HIDDEN wisdom, which God ordained before the world began UNTO OUR GLORY (1Corinthians 2:6-16, Ephesians 3:6).    These verses speak of all the things freely given us in Christ that the Spirit revealed to and through the apostles.

  (6) The RAPTURE of the Church:
Behold, I show you a MYSTERY; we shall not all sleep, but we shall all be changed, In a moment, in the twinkling of an eye, at the last trump: for the trumpet shall sound, and the dead shall be raised incorruptible, and we shall be changed (1Corinthians 15:51,52).

4. The MYSTERY of Iniquity.
For the mystery of lawlessness is already at work; only he who now restrains will do so until He is taken out of the way.  And then the lawless one will be revealed, whom the Lord will consume with the breath of His mouth and destroy with the brightness of His Coming (2Thessalonians 2:7,8).  This spirit of antichrist is already working throughout this age (the false-sowing in the Wheat and Tares and the Leaven) but it can only be fully revealed in the person of the antichrist, after the rapture when the restrainer is removed (v1-8).  The IDENTITY OF THE ANTICHRIST will be fully revealed in the Tribulation.

5. MYSTERY Babylon (Revelation 17:5,7).
This is the APOSTATE CHURCH (which REJECTS THE TRUE CHRIST).   It is developing and growing throughout the Church-Age and will be CUT OFF (spewed out) by Christ at the start of the TRIBULATION.   Apostacy in the Church is only fully revealed in the Tribulation, when the true Church is removed.  At this time the leaven will have leavened the whole lump and the church on earth will be completely apostate.   It will form into a ‘One-World Church’. As Israel were blinded for rejecting Christ, the apostate church (who reject the Biblical Christ) come under a strong delusion.   They accept and support the antichrist as leader (as happened with Hitler, a type of the antichrist) and this whole church is thus condemned (v9-12).  This judgment is not upon all who miss the Rapture but upon the remaining church.   (When Christ the Head was raised and ascended, Israel still rejected the Word.  Likewise, when Christ the Body ascends, this apostate church will reject His Word and turn to antichrist).   Antichrist will destroy this harlot-church when he sets up worship to himself.  The apostate church is marked by anti-semitism (Romans 11).
 
The Church Age in Revelation 2 and 3.