In his 1899 Harper’s Monthly essay, “Concerning the Jews”, Mark Twain concludes his reflection on the Jewish people with a question.
All things are mortal but the Jew; all other forces pass, but he remains. What is the secret of his immortality?
There is no secret.
At least not to those of us who understand Jewish history and our eternal covenant with HaShem.
The Jewish people are immortal because of their adherence to the Torah.