The Apostles are promised that they will each sit on a throne, judging the twelve tribes in the promised Kingdom.
And Jesus said unto them, Verily I say unto you, That ye which have followed me, in the regeneration when the Son of man shall sit in the throne of his glory, ye also shall sit upon twelve thrones, judging the twelve tribes of Israel.
-Matthew 19:28
The Apostle James writes his epistle to the twelve tribes:
"James, a servant of God and of the Lord Jesus Christ: To the 12 tribes in the Dispersion."
-James 1:1
James refers to them meeting in synagogues (Jas 2:2). Unfortunately, this has been sanitized by Replacement Theologians and those who will not accept that James was writing to Jews, in the dispersion, who still identified as the 12 tribes.
Of the 58 English translations available at Biblegateway.com only 8 use "synagogue" to translate the Greek "synagōgḗ / συναγωγή." Sad.
The "Expanded Bible" uses "church meeting" and notes: "the word can mean 'synagogue,' but here refers to a house church gathering." What? "CAN MEAN" synagogue? That's the actual, Holy Spirit inspired word (synagōgḗ). There is a Greek word for "church" used all through the New Testament. God doesn't need an editor.
Also, note that none of the tribes is "lost." James doesn't say, "To the two we know of, but in case you see any of the others..." In Luke 2 we meet Anna, "Anna, a prophetess, the daughter of Phanuel, of the tribe of Asher..."
The split kingdom (the two southern tribes, Judah and Benjamin vs the 10 northern tribes) is important. We see them pictured in different ways throughout the New Testament. But we assured they will be one again. The two sticks shall form one (Ezek 37:19), all 12 tribes will be called upon to witness for the Lord in the age of the Revelation (Rev 7).
Not only James, but Peter writes to this "dispersion."
"Peter, an apostle of Jesus Christ, to the elect who are sojourners of the Dispersion..."
-1 Peter 1:1
Israel is the "elect" nation of God. These two were sent "only to Jews" (Matt 10) and preached only to Jews (Acts 11). They were among the "Apostles to the Circumcision"
"They recognized that I had been entrusted with the task of preaching the gospel to the uncircumcised,[a] just as Peter had been to the circumcised. For God, who was at work in Peter as an apostle to the circumcised, was also at work in me as an apostle to the Gentiles. James, Cephas and John, those esteemed as pillars, gave me and Barnabas the right hand of fellowship when they recognized the grace given to me. They agreed that we should go to the Gentiles and they to the circumcised."-Gal 2:7-9
In the age of the Acts, God still made a distinction between Jew and Gentile in some matters.
We've covered the New Covenant in other studies. We saw that it is not for the believers of this age, but it is reserved for a united Israel in a future day.
“The days are coming, declares the Lord,
when I will make a new covenant
with the people of Israel
and with the people of Judah....
This is the covenant I will establish with the people of Israel
after that time, declares the Lord.
I will put my laws in their minds
and write them on their hearts.
I will be their God,
and they will be my people."
-Heb 8:8,10
Note the covenant is to the separated kingdoms (Israel and Judah), yet they will become one again (Israel).
Let us not rob from their promises. And why would we want to? We should be looking for our hope in "the far above the heavens" (Ephesians).