Two insights of the Netziv you can take home to your Shabbos table:
1) Why specifically are those who made the tent fabrics of the Mishkan described as “chacham lev”? The Seforno answers that making the fabric required special skill, as there were separate designs visible on either side. The Netziv uses this issue as a way to explore the halachic question of whether hidur takes precedence over zerizus. Building the Mishkan entailed many projects, from tent fabric to keilim. One might have thought it better not to jump into the first project, but to delay until work was needed on kli, as the kelim had more kedusha than the tent walls. The “chacham lev” was the person who realized that the potential hidur of working on an item with greater kedusha is less significant than the value of demonstrating zerizus by immediately contributing. (A thought: perhaps this same issue of hidur vs. zerizus underlies the criticism of the Nesi’im cited by Rashi 35:27.)
2) The Netziv notes that the lists of items made for the Mishkan follows the pattern of naming the materials used and then describing the work process. A few examples: “VaYa’as es hamenorah zahav tahor, miksha asah….” (37:17); “VaYa’as es mizbach haketores atzei shitim…” (37:25); “Vaya’as es mizbach ha’olah atzei shitim…” (38:1.) The one exception to the rule is the curtain which hung at the Mishkan’s entrance, which is first described as “ma’aseh rokeim”, made using a professional embroidery process, and then the colors and fabrics used follow (38:18). The Netziv writes that the Torah reversed the order to stress the beauty of the embroidery, which surpassed the beauty of the other tent walls. Why is this significant? Even though the entranceway was far removed from the kodesh kodashim and other more sanctified areas of the Mishkan, it was the first thing that a person noticed when he/she approached the Mishkan. It is not enough for a person to enter the Mishkan and only then become sensitive to being in a makom kadosh; that sensitivity to kedusha, that preparedness and expectation for the beauty and holiness of the Mishkan must be imparted at the entranceway, before one crosses the threshold. One simple mussar haskel: sharing the beauty of what will be accomplished before a project starts is one way to build enthusiasm for the work ahead.