In this week's parsha, the Jewish nation is commanded to build the mishkan with all of its details. The basic structure consisted of forty eight wooden boards covered with several layers of curtains. The Torah tells us that the wood used for the boards was 'atzei shittim,' usually translated as acacia wood. The Midrash Rabbah to our parsha (35:1) says that God specifically chose this tree because it does not bear fruit. The message, says the Midrash, is that we should be careful about destroying fruit trees. If God, to whom everything in the universe belongs, uses non-fruit trees to build His own house, all the more so should a human being be careful to build his own structures out of non-fruit-bearing trees. Aside from this lesson about destroying fruit trees for building purposes, this Midrash may carry other, less obvious messages as well.
In commanding the production of curtains for the Mishkan, the Torah says, "And you shall make the Mishkan of ten curtains" (Shemos, 26:1). Rashi in parshas Vayakheil points out that the Mishkan is named after the lower layer of curtains. Rabbi Eliyahu Meir Bloch, in his sefer, Pninei Da'as, comments on our verse that we would really expect the Torah to refer to the boards as the Mishkan, since the boards give the structure physical stability, while the curtains only serve as a covering. That the curtains define the Mishkan tells us that it is not necessarily the strongest physical aspect of the Mishkan that defines it and constitutes its true foundation. Similarly, it is not the material aspects of the Jewish nation that define its nature, the essence of the nation being the spirituality of its members. Within the context of Rabbi Bloch's remarks, the fact that the wood used for the boards was not fruit-bearing takes on added significance. The simple acacia wood that does not bear fruit further de-emphasizes the centrality of the boards in defining the mishkan, turning our focus away from the physical strength of the structure.
Another lesson can be learned from the use of a non-fruit tree in the mishkan. The Aron was also made of atzei shittim, which was then overlaid on the inside and outside with gold. The Aron, which housed the tablets and the Sefer Torah written by Moshe, represents the written law, while the Menorah, the Rabbis tell us, represents the oral law. The Chasam Sofer writes that the designs on the Menorah – the knobs, the flowers, etc. – are symbolic of the details of the oral laws and the many elaborate explanations given by students over the generations. All of the laws stem from one main body, the written Torah. Perhaps this explains why the core of the Aron, which represents the written law, was made of ‘atzei shittim,’ a tree that does not produce new fruit every season. The basic text of the written law is unchanging; it does not produce “fruit.” The oral law explains the true meaning of the written law, but the text of the written law, represented by acacia wood, is immutable.