The first Christians as part of Christ Yeshua's Christian Church, were of what nationality, yes they were Jews from Judea as part of the former Israel.... Before the early Christian Church in Jerusalem were supplanted by the Roman "church", which excludes Jews as partakers in Christianity, unless they forfeit their Judaic identity and customs in obedience to God's commandments relevant for them.
bit.ly/EarlyJerusalemChurch
Glad that you agree that both the Jews and Gentiles are "joint-heirs" (God's covenant children of Abraham, through whom all the nations of the earth would have been blessed) and a "joint-body" (the Christian Church Body of Christ consisting of both Jewish and Gentile believers at its fulfillment at the second coming of Christ Yeshua in the clouds, with the rapture into the clouds of resurrected and alive Jewish and Christian believers) and "joint-partakers" of the promise of salvation by the blood sacrifice of Christ Yeshua in accordance with the Gospel of Christ Yeshua, which is God the Father, Son and Holy Spirit's renewed covenant with His chosen, believing part of mankind from all tribes, tongues and nations including Jews and Gentiles.
Matthew 24 (New King James Version)
14And
this gospel of the kingdom will be preached in all the world as a witness to all the nations
(not excluding the Jewish nation in Judea as part of the former united Israel), and then the end will come.
Acts 1 (New King James Version)
8But you shall receive power when the Holy Spirit has come upon you; and you shall be
[c]witnesses to Me in Jerusalem, and in all Judea
(not excluding the Jewish nation in Judea as part of the former united Israel) and Samaria, and to the end of the earth.”
Ephesians 3 (New King James Version)
The Mystery Revealed
1For this reason I, Paul, the prisoner of Christ Jesus for you Gentiles—
2if indeed you have heard of the
[a]dispensation of the grace of God which was given to me for you,
3how that by revelation He made known to me the mystery (as I have briefly written already,
4by which, when you read, you may understand my knowledge in the mystery of Christ),
5which in other ages was not made known to the sons of men, as it has now been revealed by the Spirit to His holy apostles and prophets:
6that the Gentiles should be fellow heirs, of the same body, and partakers of His promise in Christ through the gospel, 7of which I became a minister according to the gift of the grace of God given to me by the effective working of His power.
Purpose of the Mystery
8To me, who am less than the least of all the saints, this grace was given, that I should preach among the Gentiles the unsearchable riches of Christ,
9and to make all see what
is the fellowship of the mystery, which from the beginning of the ages has been hidden in God who created all things
[c]through Jesus Christ;
10to the intent that now the
[d]manifold wisdom of God might be made known by the church to the
[e]principalities and powers in the heavenly
places, 11according to the eternal purpose which He accomplished in Christ Jesus our Lord,
12in whom we have boldness and access with confidence through faith in Him.
13Therefore I ask that you do not lose heart at my tribulations for you, which is your glory.
Appreciation of the Mystery
14For this reason I bow my knees to the Father
[f]of our Lord Jesus Christ,
15from whom the whole family in heaven and earth is named,
16that He would grant you, according to the riches of His glory, to be strengthened with might through His Spirit in the inner man,
17that Christ may dwell in your hearts through faith; that you, being rooted and grounded in love,
18may be able to comprehend with all the saints what
is the width and length and depth and height—
19to know the love of Christ which passes knowledge; that you may be filled with all the fullness of God.
20Now to Him who is able to do exceedingly abundantly above all that we ask or think, according to the power that works in us,
21to Him be glory in the church by Christ Jesus to all generations, forever and ever. Amen.
Hebrews 8 (New King James Version)
A New Covenant
7For if that first
covenant had been faultless, then no place would have been sought for a second.
8Because finding fault with them, He says: “Behold, the days are coming, says the Lord, when I will make a new covenant with the house of Israel and with the house of Judah—
9not according to the covenant that I made with their fathers in the day when I took them by the hand to lead them out of the land of Egypt; because they did not continue in My covenant, and I disregarded them, says the Lord.
10For this
is the covenant that I will make with the house of Israel after those days, says the Lord: I will put My laws in their mind and write them on their hearts; and I will be their God, and they shall be My people.
11None of them shall teach his neighbor, and none his brother, saying, ‘Know the Lord,’ for all shall know Me, from the least of them to the greatest of them.
12For I will be merciful to their unrighteousness, and their sins and their lawless deeds I will remember no more.”
13In that He says, “A new
covenant,” He has made the first obsolete. Now what is becoming obsolete and growing old is ready to vanish away.