“…These are the accounts of the Mishkan, the Mishkan of the Testimony, as they were overseen by Moshe…” – Shemos 38:21

אֵלֶּה פְקוּדֵי הַמִּשְׁכָּן מִשְׁכַּן הָעֵדֻת אֲשֶׁר פֻּקַּד עַל פִּי משֶׁה – שמות לח, כא

The total weight of all the gold, silver, and copper that was donated for the Mishkan is recorded in Parshas Pikudei.  No mention is made, however, of the monetary worth of these precious metals, only their weight.

This teaches us a valuable lesson. The difference between weight and worth is that weight measures only the mass of an object, while worth reflects the object’s distinctiveness and quality. In a spiritual sense, these two components can be found in varying scales in all our “contributions” toward making a Mishkan, a dwelling place for G-d in this world. The weight, or mass, of the contribution is the practical deed it involves, such as the actual observance of a mitzvah. The worth, or quality, of the contribution is the intent and inner devotion with which that good deed is done.

One might assume that actions that lack any inner feeling or intent serve no purpose whatsoever in making the Mishkan. What value does uninspired physical action contribute toward making G-d manifest in our lives?

The Torah therefore gives an accounting of the weight of the donations, to teach us that Moshe attributed significance not only to the worth of the donations but also to their weight.  For even the mass, the practical deeds alone, was worthy enough in the eyes of Moshe to be counted and recorded.

—Likkutei Sichos vol. 26, p. 279