The Midrash Tanchuma (Vayakhel 1) teaches: “Every time a man increases his good deeds (and mitzvos), he adds to his good name. You find that a man is known by three names: the name which his father and mother call him; the name by which other men call him; and the name he earns for himself. Proof of this is Betzalel, who was granted the privilege of building the Mishkan because he had earned a good name. What is the source of this idea? From the name He called him: ‘See, Hashem has called by name, Betzalel.’ (Which can be read as b’tzeil Keil, ‘in the shadow of G-d’).” An intriguing statement which begs elucidation. What is special about the name that one earns from himself? Why is it better than the name he was given at birth or the name by which his friends call him?
Horav Eliezer Kahanov, zl (Rosh Yeshivah, Torah Vodaas) explains the concept of shem she’kanah l’atzmo, “The name that he earns for himself,” as the name by which he is recognized, to the point that it becomes a synonym for his birth name. For example, Chananyah, Mishael and Azaryah became synonymous for one who is mekadesh shem Shomayim b’rabim, “publicly sacrifices himself for the glory of the Almighty.” Thus, when the name of one these three is mentioned, one immediately thinks of Kiddush Shem Shomayim.
Anyone who devotes himself whole-heartedly to serving Hashem becomes a symbol of the greatness that he has achieved, and he is ultimately identified with that symbol, that specific characteristic. When one mentions the Gaon of Vilna, we think of brilliance, unparalleled diligence and assiduousness in Torah. The Chafetz Chaim is the symbol of righteousness and devotion, as he was the individual who altered our halachic appreciation of Shulchan Aruch, Orach Chaim with his Mishnah Berurah. He also transformed how we think and speak concerning others through his Shemiras Halashon. These are but a few examples but the idea of a person symbolizing his unique quality applies to many. A shem tov is an identity; it is the name that we earn.
This is Chazal’s message concerning Betzalel’s good name. Betzalel – b’tzal Keil – in Hashem’s shadow: Betzalel’s name was the identity which he earned as a result of his devotion to Hashem.