(Rav Yitzchak ben Yehudah Abba initially published his Ladino commentary on Sefer Yeshayahu in Salonica, 1892. It was later translated & adapted into Hebrew by Rav Shmuel Yerushalmi, and then into English by Yehoshua Starrett, pages 277-278).
זֶה יֹאמַר לַיהוָה אָנִי, וְזֶה יִקְרָא בְשֵׁם-יַעֲקֹב; וְזֶה, יִכְתֹּב יָדוֹ לַיהוָה, וּבְשֵׁם יִשְׂרָאֵל, יְכַנֶּה
This one shall say, "I am Hashem's," and that one shall call himself in the name of Yaakov, and this one will write with his hand "For Hashem," and will adopt the name Yisrael.
- The ones who say, "I am Hashem's" — the tzaddikim
- The ones who call themselves by the name of Yaakov — the small ones, the children of the intentional sinners (reshaim).
- The ones who write by their own hand "For Hashem" — the baalei teshuvah.
- The ones who adopt the name Yisrael — the sincere converts.
And that is what it means.
But according to the Me'am Lo'ez, the verse contains yet another interpretation:
And God's blessings will be specifically for His chosen people, even though other nations may claim the same.
Even if they say, "I am for God," and call themselves in Jacob's name, even if they commit themselves to God in writing and call themselves the new "Israel," God's chosen will remain Jacob's physical seed.
How many individuals and groups go around claiming they represent God's Will, they are for God and belong to God, and steal names for themselves from Yaakov and his sons (like Ephraimites, etc.)?
How many insincere and/or unaware "converts" (from the Reform, Conservative, and irresponsible Orthodox clergy) go around proclaiming themselves as Jews—many truly believing they are?
How many from the Russian provinces acquired fake certificates & ketubahs to lie about being Jewish to come to Israel and enjoy the benefits?
And what about the 2 big religions who claim to be from God, pretenders to the Chosen Nation?
It doesn't matter what people claim, whether in words or in writing.
The real Bnei Yisrael remain as Hashem's forever.
Furthermore, the Me'am Lo'ez explains that sincere converts, though not from the physical seed of Yaakov, will still be considered as if they are:
But there will be those among them who will earnestly convert and proclaim their bodies and souls to God.
These ones can also be called "Jacob-Israel" and will be added to the ranks of the Israel-born.
He knows who TRULY proclaimed their bodies and souls to Hashem...
...and He knows who did not.
A lot of people are being fooled. But Hashem can never be duped.
Not only are the sincere ones called "Yaakov-Yisrael" (even though they did not actually descend from Yaakov), but the sincere conversion of their soul enables them to be considered equal to the born Yisrael.
And finally, to all the true Jews out there:
They will all be gathered together at the End of Days, one by one, each one for his own merit.
With everything going on, it's reassuring to read of Hashem's individual one-on-one supervision for each person.
No Jew left behind.