The Baal Shem Tov waged a fierce battle against the Frankists throughout his life.
Yet when they had converted to Catholicism, he grew deeply upset and exclaimed that “The Shekhinah cries out for their sake” (Shivkhei haBesht).
He explained that as long as a limb is connected to the body, even if it has shriveled, it may still recover.
But once the limb is severed, it is gone forever.
And every Jew is a limb of the Shekhinah.
–Rabbi Adin Steinsaltz