For Man is Like a Tree of the Field (Deut. 20:19)

Rabbi Shneur Zalman of Liadi, founder of Chabad Chasidism, once remarked to a Torah scholar during his first private audience: "The Torah states, 'For man is like a tree of the field.' A tree that does not bear fruit is a barren tree. A person can be fluent in the entire Talmud and still be 'barren,' G-d forbid. A Jew must produce 'fruit.' For what benefit is there in your learning and Divine service if you do not bear 'fruit' - if you do not cause your light to shine upon another Jew?"