Just what it says, but just in case, let's put the whole verse here.
Ephesians 3:6 to be specific, that the Gentiles are fellow heirs and fellow members of the body, and fellow partakers of the promise in Christ Jesus through the gospel, (NASB)
So that the Gentiles through Jesus are now heirs to the kingdom of heaven, just like the Jews were before. That the Gentiles are part of the same body of Christ, that the Jews were before, that the Gentiles were now partakers of the promise which is eternal life through Jesus Christ, just as the Jews were before.
Wow, I know I'm new here and all, but I must disagree with this. Sorry.
That God would save people like you and me was a MYSTERY hid in God!
It was UNSEARCHABLE!
Acts 22:21 KJV And he said unto me, Depart: for I will send thee far hence unto the Gentiles.
Ephesians 2:11-12 KJV Wherefore remember, that ye being in time past Gentiles in the flesh, who are called Uncircumcision by that which is called the Circumcision in the flesh made by hands; 12 That at that time ye were without Christ, being aliens from the commonwealth of Israel, and strangers from the covenants of promise, having no hope, and without God in the world:
Ephesians 2:13 KJV But now in Christ Jesus ye who sometimes were far off are made nigh by the blood of Christ.
Ephesians 3:1-5 KJV For this cause I Paul, the prisoner of Jesus Christ for you Gentiles, 2 If ye have heard of the dispensation of the grace of God which is given me to you-ward: 3 How that by revelation he made known unto me the mystery; (as I wrote afore in few words, 4 Whereby, when ye read, ye may understand my knowledge in the mystery of Christ) 5 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;
Ephesians 3:6 KJV That the Gentiles should be fellowheirs, and of the same body, and partakers of his promise in Christ by the gospel:
(fellowheirs with those who first trusted in Christ beginning with Paul (1 Timothy 1:13-16 KJV), and included the Romans, Corinthians, Galatians and Thessalonians)
^^^^^^^^^
Ephesians 1:12 KJV That we should be to the praise of his glory, who first trusted in Christ.
Ephesians 1:13 KJV In whom ye also trusted, after that ye heard the word of truth, the gospel of your salvation: in whom also after that ye believed, ye were sealed with that holy Spirit of promise, 14 Which is the earnest of our inheritance until the redemption of the purchased possession, unto the praise of his glory.
The word of truth, the gospel of your salvation is the gospel of Christ, the power of God unto salvation (Romans 1:16-17 KJV, Ephesians 1:13 KJV)!
The gospel of Christ:
1 Corinthians 15:1-4 KJV Moreover, brethren, I declare unto you the gospel which I preached unto you, which also ye have received, and wherein ye stand; 2 By which also ye are saved, if ye keep in memory what I preached unto you, unless ye have believed in vain. 3 For I delivered unto you first of all that which I also received, how that Christ died for our sins according to the scriptures; 4 And that he was buried, and that he rose again the third day according to the scriptures:
It is the ONLY gospel that establishes you into the Body of Christ:
Romans 16:25-27 KJV 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, 26 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: 27 To God only wise, be glory through Jesus Christ for ever. Amen.
Ephesians 3:7-9 KJV Whereof I was made a minister, according to the gift of the grace of God given unto me by the effectual working of his power. 8 Unto me, who am less than the least of all saints, is this grace given, that I should preach among the Gentiles the UNSEARCHABLE riches of Christ; 9 And to make all men see what is the fellowship of the mystery, which from the beginning of the world hath been hid in God, who created all things by Jesus Christ:
1 Timothy 2:4 KJV Who will have all men to be saved, and to come unto the knowledge of the truth.
Titus 2:11 KJV For the grace of God that bringeth salvation hath appeared to all men,
The only gospel that will save you today is the gospel that was revealed to and through the apostle Paul by the risen, glorified Lord Jesus Christ.
Galatians 1:11-12 KJV But I certify you, brethren, that the gospel which was preached of me is not after man. 12 For I neither received it of man, neither was I taught it, but by the revelation of Jesus Christ.
Ephesians 6:19-20 KJV And for me, that utterance may be given unto me, that I may open my mouth boldly, to make known the mystery of the gospel, 20 For which I am an ambassador in bonds: that therein I may speak boldly, as I ought to speak.
2 Timothy 2:15 KJV Study to shew thyself approved unto God, a workman that needeth not to be ashamed, rightly dividing the word of truth.