The good news (gospel) of Christ is that Christ needed to suffer and die as the perfect sacrifice for man's sin and be raised from the dead.  The good news (gospel) of Christ is also that this Jesus is the promised Christ.  Paul spent three weeks showing the Judeans in the synagogue at Thessalonica this gospel from the scriptures of the Old Testament.  This same good news (gospel) was taught by Peter to the Judeans at Jerusalem on the day of Pentecost.

Acts 2:22-24
   Ye men of Israel, hear these words; Jesus of Nazareth, a man approved of God among you by miracles and wonders and signs, which God did by him in the midst of you, as ye yourselves also know:
   Him, being delivered by the determinate counsel and foreknowledge of God, ye have taken, and by wicked hands have crucified and slain:
   Whom God hath raised up, having loosed the pains of death: because it was not possible that he should be holden of it.

   This good news (gospel) of Christ is that which must be preached, heard and believed if a man or woman is to get saved according to the scriptures as recorded in Romans 10:9-10.  This is the same good news (gospel) of Christ that Peter presented when God first sent him to the Gentiles in Acts Chapter 10.

Acts 10:38-40
   How God anointed Jesus of Nazareth with the Holy Ghost and with power: who went about doing good, and healing all that were oppressed of the devil; for God was with him.
   And we are witnesses of all things which he did both in the land of the Jews, and in Jerusalem; whom they slew and hanged on a tree:
   Him God raised up the third day, and shewed him openly;

   The four Gospel records of Matthew, Mark, Luke, and John present the record of the walk of Jesus of Nazareth and show in detail how he fulfilled the law of the Old Testament, suffered, died for our sins, and was raised again.  They complete the Old Testament.  Paul presented this same good news (gospel) of Christ each time he introduced the Word of God to a new group of people.

Acts 13:28-30
   And though they found no cause of death in him, yet desired they Pilate that he should be slain.
   And when they had fulfilled all that was written of him, they took him down from the tree, and laid him in a sepulchre.
   But God raised him from the dead:

   This good news is that which must be believed about Jesus Christ.  Yet this is only the beginning of the good news.  God revealed to the Apostle Paul the mystery of the good news (gospel) of the grace of God to fulfill or to "fully preach" the Word of God.

Colossians 1:25-26
   Whereof I am made a minister, according to the dispensation [administration] of God which is given to me for you, to fulfill [fully preach] the word of God;
   Even the mystery which hath been hid from ages and from generations, but now is made manifest to his saints:

   The good news of Christ begins with an understanding of Jesus as the Christ who fulfilled the Old Testament law, was crucified and slain, and raised from the dead.  But to fully preach and to fully understand the good news of Christ you must be taught that which came as a result of the accomplishments of Christ.  That which was revealed regarding Christ and the administration of grace in which we live today was a mystery kept secret in God Himself and not made known until it was made known to Paul.  The four Gospels do not reveal it.  Peter did not know it.  Paul was not taught it by man.  The word mystery is the Greek word "musterion."  It is used of a secret kept by a code of silence by those fully initiated into Greek religions.  God kept the mystery of the gospel hid by silence in Himself until He finally revealed it to the Apostle Paul.  Since it was revealed to Paul, Paul refers to it as "my gospel."

Galatians 1:11-12
   But I certify you, brethren, that the gospel which was preached of me is not after man.
   For I neither received it of man, neither was I taught it, but by revelation of Jesus Christ.

Romans 16:25
   Now to him that is of power to stablish 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.

   The good news (gospel) of Jesus Christ preached by Paul was Jesus Christ according to the revelation of the mystery.  Yes, Paul taught the same gospel as Peter and the other Apostles.  But he did not stop there.  He fully preached the Word of God by revealing Jesus Christ according to the revelation of the mystery.  That which God had planed for the church was a secret.   Only by reading and understanding the epistles written by Paul can we know the good news of the mystery of the grace of God toward us.

Ephesians 3:2-5
   If ye have heard of the dispensation [administration] of the grace of God which is given me to youward:
   How that by revelation he made known unto me the mystery; (as I wrote afore in few words,
   Whereby, when ye read, ye may understand my knowledge in the mystery of Christ)
   Which in other ages was not made known unto the sons of men, as it is now revealed unto his holy apostles and prophets by the Spirit;

   The good news of the grace of God includes everything available to us in our day and time thanks to the accomplished work of Jesus Christ.  Gentiles are fellow heirs with Judeans and partakers of his promise in Christ by the gospel.  The riches of this mystery is that each believer has Christ in them the hope of glory according to Colossians 1:27.

I Corinthians 2:1-2
   And I, brethren, when I came to you, came not with excellency of speech or of wisdom, declaring unto you the testimony [mystery] of God.
   For I determined not to know any thing among you, save Jesus Christ, and him crucified.

   Paul did not begin his presentation of God's Word with a knowledge of the mystery of God.  He always began with the good news (gospel) of Christ regarding salvation.  But after they got born again and had an understanding of the accomplishments of Christ he taught them about the mysteries of the grace of God.

I Corinthians 15:51-52
   Behold, I shew you a mystery; We shall not all sleep [die], 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.

   Part of the mystery of the grace of God is a knowledge of the gathering together of those who have been born again in Christ.  We have been saved from the wrath to come and we will receive spiritual bodies like unto Christ's glorious body.  This knowledge was hid in God and not made known before it was revealed unto the Apostle Paul.

I Thessalonians 4:13-18
   But I would not have you to be ignorant, brethren, concerning them which are asleep [those believers who have died], that ye sorrow not, even as others which have not hope.
   For if we believe that Jesus died and rose again, even so them also which sleep in Jesus will God bring with him.
   For this we say unto you by the word of the Lord, that we which are alive and remain unto the coming of the Lord shall not prevent them which are asleep.
   For the Lord himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God: and the dead in Christ shall rise first:
   Then we which ware alive and remain shall be caught up together with them in the clouds, to meet the lord in the air: and so shall we ever be with the Lord.
   Wherefore comfort one another with these words.

   The good news (gospel) of Christ according to the revelation of the mystery includes a knowledge of our hope for the gathering together of the church.  As long as the church of the body of Christ remains on the earth the full wrath and iniquity planned by the devil CANNOT come to pass.  Yes, iniquity is in the world and we do face a certain amount of tribulation.  But that full iniquity and wrath that is to come is held back by the presence of the church.  This is part of the mystery of the grace of God that must be understood if we are to fully preach the gospel.

II Thessalonians 2:5-7
   Remember ye not, that, when I was with you, I told you these things?
   And now ye know what withholdeth [holds the son of perdition down fast so that he cannot bring wrath to the world] that he might be revealed in his time.
   For the mystery of iniquity doth already work: only he [Christ in the believers] who now letteth [holds him down] will let [hold him down], until he [Christ in the believers] be taken out of the way.

   The good news (gospel) of Christ includes a blessed hope.  We will be taken out of the way before the devil can bring full iniquity upon the earth.  We have been saved from the wrath to come.

I Timothy 3:16
   And without controversy great is the mystery of godliness:  God [Which] was manifest in the flesh, justified in the Spirit, seen of angels, preach unto the Gentiles, believed on in the world, received up into glory.

   The good news (gospel) of the mystery of the grace of God is briefly covered in this one verse.  Godliness is a true, vital, spiritual relationship with God.  The mystery of that which we have as a result of the accomplished work of Christ includes the gift of holy spirit manifest in our flesh, spiritual justification, revelation of all that we have been given to principalities and powers in heavenly places, a holding forth of this word to the nations, a believing response by many in the world, and our gathering together in glory at Christ's return.  What a glorious day that will be!