ויעש בצלאל את הארון. הוא היה ראשון לכל כלי המשכן דכתיב פתח דבריך יאיר שהאור נברא בעולם תחלה ולכך הארון שבו התורה נתונה שנאמר כי נר מצוה ותורה אור נעשה תחלה ואין אתה מוצא שמו של בצלאל על שום כלי מכל כלי המשכן אלא על הארון לפי ששם של בצלאל מורה על שום צל אל וזהו נוטריקון של בצלאל וגם זהו שאמחז"ל שמדעתו היה סדר העשיה אמר לו משה בצל אל היית: ויעש בצלאל את הארון, “Betzalel constructed the Ark.” It was the first of the furnishings of the Tabernacle. This corresponds to what we read in Psalms 119,130: and פתח דבריך יאיר מבין פתיים, “even the preamble to the words You inscribed give light.” David referred to the “light” G–d had created on the first day prior to proceeding to creating the three dimensional universe. This is what the Holy Ark represented in the Tabernacle as the Torah it contained has been defined by Solomon in Proverbs 6,23 as: כי נר מצוה ותורה אור, “for the individual commandment is a lamp, whereas the Torah as a whole represents light itself.” The reason why you do not find Betzalel’s name associated with any of the furnishings of the Tabernacle other than the Holy Ark, is that in connection with that item Betzalel had demonstrated the degree of holy spirit which G–d had endowed him with. Moses had suggested to Betzalel to construct the Holy Ark as the first item to be made for the Tabernacle, whereupon Betzalel upon hearing this questioned it by saying to him: “are you sure? Does one not build a house before making the furniture for it?” Moses then remembered that he had forgotten the order in which G–d had told him to proceed. Our sages kept this story alive by pointing out that the meaning of Betzalel’s name בצל-אל is: ”in the shadow of G–d,” i.e. he must have been nearby when G–d instructed Moses. (Compare Talmud, tractate B’rachot folio 55)
עצי שטים. לפי שעתידין לחטא בשטים העמיד להם זה לכפר על מעשה שטים: עצי שטים, “acacia wood.” It was so named because the Israelites would commit grave sins at a location by that name. Using this type of wood was meant to help atone for that sin by the people.