Sorry whirlwind but I just don't see anywhere in scripture that states they were lost and not known of for any length of time. If you spiritualize verses you can make them say what you want and how you want. I am going to bow out of this thread now as I can see we won't agree. God's blessings be upon you my sister in Christ.
The Mystery of Christ hidden from all the ages is the fact that Gentiles have become grafted in through the Northern Ten tribes of Israel through the promise of Ephraim.
Paul taught this in Romans 9:24, Ephesians teaches it, Galations, Peter, Timothy and you can find it many places.
If you do not know the history, then you read the New Testament completely unaware of what is being said in the bulk of the scriptures.
You are correct in that the Gentiles shall be grafted in but grafting in doesn't mean the root is changed....it means the graft becomes of the root. They become one. The Gentile becomes Israel. We are the wild and the natural olive tree.
God said in Hosea that the Ten tribes would not have any children, in fact he said if one were to get pregnant that he would kill the fruit of the womb, Ezekiel and Isaiah both agree with this.
In the beginning of Hosea it says that God will have no mercy on the House of Israel called Ephraim and his ten tribes.
God said,'' They are not my people''
Please read Hosea again...to the end of the chapter:
- Hosea 1:10-11 Yet the number of the children of Israel SHALL BE AS the sand of the sea, which cannot be measured nor numbered; and it shall come to pass, that in the place where it was said unto them, Ye are not My people, there it shall be said unto them, YE ARE THE SONS OF THE LIVING GOD. Then shall the children of Judah and the children of Israel be gathered together, and appoint themselves One head, and they shall come up out of the land: for great shall be the day of Jezreel.
Paul explains this when telling you how gentiles have been grafted in through the promised resurrection of Ephraim saying,'' Not my people{Ephraim} will be called the sons of the living God.
- Romans 9:24-26 Even us, whom He hath called, not of the Jews only, but also of the Gentiles? As He saith also in Osee, I will call them My people, which were not My people; and her beloved, which was not beloved. And it shall come to pass, that in the place where it was said unto them, Ye are not My people; there shall they be called the children of the living God.
In Hosea/Osee, we are shown the Gentiles being grafted in. We are NOT told that the tribes are done away with. The Gentiles that "were not My people" become His people....they become Israel.
The Ten tribes have been lost for 2700 years now and this is historical fact.
God said it would happen and it happened.
There are two nations of Israel, The House of Judah and the House of Israel{Ephraim}
They were always two kingdom since the days of Solomon, In 722 b.c. they were lost as Prophecied.
Yes. He scattered us and that serves His purpose.
I sat for a while and wondered to myself how I would begin a debate with somebody who has never heard of the ten lost tribes.

Where is Ephraim, where is Samaria, where is Joseph, Where is the House of Israel, Where is the Northern Kingom?
Where is Gilead?
Where are the Shechemites?
Where are the oaks of Bashan and the cedars of Lebanon?
Maybe you should inquire of the nation of Israel to see where Ephraim has gone because they are unaware.
They have found Hebew writings amongst the Cherokee nation and they now accept the Cherokee as being one of the lost tribes, They are also looking to Sheba in Ethiopia considering they might have found one of their brothers.
The prophecies state that in the last days Joseph will suddenly be found and the two will become one in that day and conquer the entire world.
They mourn for their brother for this reason.
In Zechariah the Jews see a Messiah of Joseph pierced and they admit that the whole nation will mourn for this Messiah but they also know that Joseph is in the hands of Ephraim and Ephraim is no more.
In the last day, the Tents of Joseph will be found suddenly in a day and the children of Joseph will gleam in pride for their fathers.
Suddenly, millions upon millions who were once dead are found and the stick of Ephraim will become one with Judah.
This has never happened.
Can you read all these names?
Read Hosea again and wonder to yourself why Paul quotes the Prophcy of Ephraim's resurrection concerning gentiles.
Read it slowly because what it says exactly is that God would kill and drive Ephraim{Ten tribes of Israel} into the nations and there they would become gentiles.
It says that they would have no children and God would not accept them back until they became gentiles.
They did become gentiles and as such, they have the right to return if they repent and do what is required of Ephraim to do.
This is why Paul explains how gentiles are grafted through the promised resurrection of the house of Israel called Ephraim.
Jesus called Gentiles from Galilee, from the land iof Naphtali and Zebulun and all the ten tribes specifically after his resurrection.
He sent his spirit before the disciples into the land of Gentiles which belonged to Ephraim to call forth the lost children of the House of Israel called Ephraim.
Only as Gentiles would Ephraim be accepted.
Even the Talmud speaks of it.
If you do not know that Joseph is lost, how will you be found?
If you do not know that the House of Israel is lost then how do you have a covenant?
If you do not know that Gilead has been threshed, how will you stand in the void?
If you do not know that Joseph's bones call out for you, how will you heed the call?
If you do not know the responsibilities of Ephraim on his return, How will you be gathered?
You wont, If you have not stood in the void and filled the gap in Joseph, you have no covenant because the covenants and promises are only given to Joseph and Judah and Joseph is in the hand of Ephraim.
Everything you quoted in the New Testament backs up the facts I am giving you.