Yes that would be Israel.
Israel is the name of the nation of the children of the kingdom. Father Adam and Mother Eve are the ones that made Procreation possible for the children of the kingdom to have physical bodies like they have physical bodies.
And they paid a price to start Procreation, as Highlighted by Jesus His Pre-Eminence in John 12:24
24 Verily, verily, I say unto you,
Except a corn of wheat fall into the ground and die, it abideth alone: but if it die, it bringeth forth much fruit.
This is the Law for Procreation.
Then in parable of
wheats and tares, the wheat are the children of the kingdom, the tares are bundled as chaff for the fire. Tares are not chidren of the kingdom..
The first Man Adam, and his model type Eve, are that corn of wheat that had to die to begin Procreation. And like the seed of tree that is planted, and that seed grows into a tree, the seed that was planted is lost forever. It is impossible to locate that very seed again. In the same way, If Jesus His Pre-Eminence did not bail them out of hell, by taking their place as that seed that had to die, then they would have been lost for all eternity.
That means that the Law for Procreation would have held them down forever, and they would never have been able to be resurrected.
That is why they are the lost sheep of Israel.