Chovot Halevavot, the classical work on Jewish ethics, was authored by Rabbi Bachya ben Yosef ibn Paquda (the first "Rabbeinu Bechayei") on or before 1161, and translated into Hebrew from the original Arabic by the famed translator R. Judah ibn Tibbon in 1167. It was first published on the 25th of Tevet of the year 5319 from creation (1559).
Often, anxiety takes root because a person’s external character is incompatible with his or her inner self.
The anxiety may dwell upon other issues and obsessions—but none of these are the true underlying cause.
Most souls can tolerate a few inconsistencies. But others are sensitive to every nuance.
As soon as some aspect of their lifestyle is not attuned to the purity of the essential self, the entire person is thrown off balance.
That is why, for a Jew, being more careful about the mitzvot will often diminish anxiety.