Commentator on Chumash. Though a distinguished Talmudist, Rabbi Levi never held a rabbinical office. He earned a livelihood most probably by the practice of medicine
Rabbi Levi ben Gershon devoted his entire life to spreading the light of knowledge among his brethren and to the promotion of science and tolerance in the world at large. The descendant of a great Jewish family that had lived in France for many years and had been among the active leaders of Jewish life, Rabbi Levi showed his extraordinary capabilities at a very early age. Not only did he master the world of the Talmud, but by the age of thirty he was an accomplished physician whose services were sought after by the noble courts of Southern France. At the same time he had acquainted himself thoroughly with the fundamentals of all natural sciences known in his days. His universal genius enabled him to overthrow many of the widely accepted astronomical theories. He wrote a treatise in which he criticized and corrected the faults of the Ptolemean system, then as yet fully recognized. Thus he anticipated much of the work done by the great scientists of later days. Not only did he excel in the theory of astronomy, but he invented also an instrument which enabled the scientists to study and observe the workings of the stars and planets. His book describing this invention and his general theory on astronomy made such a deep impression upon his contemporaries that Pope Clement VI, himself deeply interested in science, had it translated into Latin. As "Magister Leo Hebraeus," Rabbi Levi ben Gershon (known also as Gersonides) figured as one of the authorities of the late Middle Ages on astronomy. His inventive spirit made him also the forerunner of another great invention, the camera. He produced a model of a "camera obscura" that anticipated the most characteristic features of the modern camera developed more than five centuries later. Mathematics and the study of nature were other sciences which Rabbi Levi ben Gershon mastered thoroughly. No wonder he was considered one of the greatest universal scholars of his age.
Rabbi Levi ben Gershon, or Gersonides, occupies one of the highest places among Jewish philosophers after Maimonides. Gersonides wrote many commentaries on the writings of` the famous philosopher Averroes. But his most important philosophical work is his "Milchamoth Hashem" (The Wars of the Lord). In this work Rabbi Levi ben Gershon follows in the footsteps of Maimonides in an attempt to reconcile religion and philosophy (especially of the Aristotelian school of thought. Although, of course, Rabbi Levi ben Gershon adhered strictly to Jewish traditions, as did Maimonides, his philosophical works were frowned upon by the rabbinical authorities of his time.
The RaLBaG's deeply religious nature becomes apparent in his great commentaries to the Chumash to parts of the Prophets and Scriptures, which have endeared him to all students of Tenach down to our very days. This is due not merely to the content of the commentaries, but also to the most beautiful Hebrew style which he uses to express his deep thoughts. The RaLBag's extensive Talmudic knowledge, acquired over many years of study, is clearly evident in his commentaries. Part of these commentaries which contain the RaLBag's ethical teachings, were published separately under the name "Toalioth" (Benefits), and they belong to the most popular works of Jewish ethics written in those days. Less known than his commentary to the Tenach is the RaLBaG's commentary to the Mishnah called "Yesod Hamishnah" (Foundation of the Mishnah) which bears witness to his great knowledge of Halachah (Jewish Law). Rabbi Levi ben Gershon wrote many poems, especially dirges, in which he bewailed the terrible persecution suffered by his brethren in France.
These persecutions never seemed to end. After the cruel expulsion of the Jews from France by King Phillip IV, the once flourishing Jewish communities never recovered fully, though the Jews were invited to return to France by King Ludwig X about nine years later. King Phillip V who succeeded the latter, also tried to encourage the Jews to resettle in France in great numbers. But the enemies of the Jews who enjoyed great influence in the church and state continued to harass the poor Jews.
Then a most terrible catastrophe befell the Jews of France by the Shepherd's Uprising, when an ignorant shepherd began to tell tales of a "heavenly mission" commanding him to start a crusade against the Arabs. He gathered an army of 40,000 men and began his "holy" crusade by massacring defenseless Jews. Some 120 Jewish communities were destroyed by those cruel "shepherds."
Rabbi Levi's heart bled for his poor, suffering brethren, and he used his great influence at the Papal Court in Avignon and his acquaintance with other notables to induce them to take under their protection thousands of Jewish refugees who were fortunate enough to escape the wave of massacres that swept all over France and destroyed one great Jewish center after another.
Rabbi Levi ben Gershon died in the year 5104 (1344) at the age of fifty-six.
May the merit of the Tzadik Rabbi Levi ben Gershon (Ralbag) protect us all. Amen