“G‑d next instructed the Jews how they were to construct the Tabernacle itself. The roof of the Tabernacle was to be formed out of three layers of material: a woven tapestry, a cover made of goat’s hair, and a cover made of the skins of rams and another, now-extinct animal. The walls were to be made out of vertical planks of acacia wood.
You must make the planks for the Tabernacle out of acacia wood, [placed] vertically. Exodus 26:15
The Hebrew word for “acacia” (shitah) means “bending.” The acacia tree is called the “bending” tree because it bends to the side as it grows, rather than growing straight up. The Hebrew word for “foolishness” (shetut) is another form of this word, since foolishness is an act of “bending” from the path dictated by logic.
Foolishness can be either holy or unholy. Unholy foolishness is the illogical thinking that leads us to go against G‑d’s will. Holy “foolishness” is our willingness to go beyond the strict requirements of the Torah in fulfilling our Divine mission or in refining ourselves.
Allegorically, then, placing the “bending” acacia planks vertically means using our power to be “foolish” for holy purposes. We can thereby turn this often negative character trait into a positive force in our lives, enabling us to reach levels of dedication to G‑d and union with Him that we would not be able to reach otherwise.1 Sefer HaMa’amarim 5710, p. 114.