“Every man whose heart lifted him came forward. And every person whose heart moved him brought the offering of Hashem for the creating of the Ohel Moed, all of its components and the sacred garments.” (Shemot 35:21)
Hashem commanded Bnai Yisrael to build a Mishcan – a Tabernacle. The Mishcan was constructed from materials provided and contributed by Bnai Yisrael. Our pasuk describes the response of the nation to Moshe’s request to supply these materials. In his comments on this passage, Rabbaynu Yonatan ben Uziel explains that the craft-people who build the Mishcan were guided by the spirit of prophecy. Why did they require this spirit of prophecy to perform their tasks? In order to answer this question, we must identify and understand a fundamental paradox within the commandment to build the Mishcan.
One of the interesting issues that is discussed repeatedly in the Talmud is whether we can rely on the accuracy of measurements. Let us consider a simple case that illustrates this issue. On Succot we are required to live in a succah. The most fundamental element of a succah is its roof. The roof must be composed of branches or a similar substance. We cannot use a metal poles or even wooden poles that have been manufactured to the extent that they are regarded as vessels. The Mishne discusses a succah whose sechach – roof is composed of a combination of suitable and unsuitable material. The two materials are place on the roof in an alternating pattern so that the quantity of the suitable material is exactly equal to the unsuitable material. The Mishne rules that this succah is acceptable. The Talmud observes that according to some authorities in order for a structure to be regarded as a succah only half of its roof must be covered with suitable sechach. A majority of the roof need not be covered with suitable sechach. Apparently, the Mishne supports this position. The implication of this discussion is that if we assume that we cannot relay on the exactness of the measurements of the two substances, the structure could not be regarded decisively as a suitable succah. This is because we could not be sure that the suitable sechach is exactly equal in quantity to the unsuitable material.
In short, the Sages disagree as to whether we can assume that measurements are exact. Some Sages maintain that we can make this assumption. Others argue that we cannot make such an assumption. If we assume that measurements can be exact, then the structure described in the Mishne is a suitable succah, without qualification. However, if we assume that measurements cannot be regarded as exact, then the structure would not be suitable unless a marginal quantity of sechach is added. This additional quantity of sechach would assure that – in fact – the sechach was at least equal to the unsuitable substance.
The same dispute extends to the measurement of events as being simultaneous. The Sages that contend that measurements can be regarded as exact, also assert that we can assume that two events that appear simultaneous actually have occurred at the same moment. The Sages that do not accept measurements as being exact, also deny that two apparently simultaneous events can be regarded as truly having occurred at the same moment.
At first glance, this dispute seems difficult to understand. It is empirically evident that it is remarkably difficult to exactly measure any quantity. Even if a measurement seems to be exact, more careful examination will indicate that it is not. Certainly, it is nearly impossible to conclude that two events are precisely simultaneous. Therefore, it would seem that the more reasonable position is to assume that measurements are not exact.
We can gain an insight into this dispute through another discussion in the Talmud. The Talmud in Tractate Bechorot attempts to resolve the dispute between the Sages on this issue. The Talmud suggests that the dispute can be resolved through considering the Torah’s commandment to build a Mishcan. The Torah provides exact measurements for each of the elements of the Mishcan. Precise dimensions are delineated for the Aron – the ark, the Shulchan – the Table that held the Shew Bread, and every other component of the Mishcan. The builders of the Mishcan were required to build the components to these exact specifications. They could not deviate from any of the specified dimensions. The Talmud asserts that this proves that we can rely on the precision of measurements! However, the Talmud rejects this proof. It explains that it is true that the Torah commands us to build a Mishcan and provides exact dimensions. However, the dimensions described by the Torah were not precisely achieved. Instead, the builders did their best to construct the Mishcan and its components according to these dimensions. However, because of the innate imperfection of any human measurement, they were not successful.
This discussion is difficult to understand. The Talmud’s discussion begins by assuming that the Torah required the Mishcan to be built to precise measurements. This is offered as a proof to the opinion that measurements can be regarded a precise. However, as explained above, it is virtually impossible to make an exact measurement. How can the Torah command us to perform the impossible?
This question suggests an important insight into the Sages’ dispute regarding the precision of measurements. As we have explained, the Mishcan presents a paradox. We were required to build the Mishcan according to exact specifications. Yet, precise measurement is virtually impossible! There are two obvious approaches to resolving this paradox.
One possibility is that the dimensions outlined in the Torah represent targets. They are impossible to precisely achieve but in constructing the Mishcan the builders were provided with a model towards which they were required to strive. The actual Mishcan was not an exact embodiment of this model. It is the closest possible actualization of the model.
The second possible resolution of this paradox is that the specifications must be achieved. An approximation is not adequate. However, the Torah accepts an empirical standard for all measurements. In other words, if a measurement is empirically met, the Torah regards the measurement as precise.
Let us now return to the discussion in the Talmud. The Talmud initially asserts that the requirement to build the Mishcan and its components to exact specifications indicates that we can rely on the precision of measurements. This proof can now be understood. The proof is based upon the assumption that the Torah’s standard of measurement is empirical. If the builders of the Mishcan carefully measured their work and all of their empirical measurements indicated that the design specifications had been met, then the standard of measurement was satisfied. In other word, if empirical measurement indicated that the Mishcan had been build exactly to specification, then according to the Torah’s standards the Mishcan was regarded as built exactly according to its specifications.
However, the Talmud rejects this argument. It suggests that – in fact – empirical measurements are not regarded as precise. Instead, in providing exact specifications for the Mishcan, the Torah created design targets. The Torah recognizes that these targets cannot be precisely achieved. However, it is not necessary to precisely achieve these specifications. They are a target. The Mishcan was acceptable because it was the closes possible embodiment of the required dimensions.
This analysis provides an explanation of the dispute between the Sages. The Sages recognize that it is virtually impossible to achieve precise measurements. The Sages that contend that measurements can be regarded as exact do not dispute this issue. However, they contend that in establishing measurements the Torah only requires that the measurements be met to an empirical level of precision. When the measurement has been empirically achieved, the Torah’s requirement is satisfied. However, the Sages who maintain that precision is impossible, argue that the measurements of the Torah are exact requirements that cannot be satisfied at an empirical level of precision. If this is the case, they must assume that Torah’s specifications for the Mishcan are intended as design targets but not absolute standards.
The Talmud offers another resolution of the paradox of the Mishcan. The resolution is quite enigmatic. It consists of a passage from Divrei HaYamim – Chronicles. King David instructed his son Shlomo to build the Bait HaMikdash – the Temple. He provided Shlomo with precise instructions. He explained to Shlomo that he was providing him with precise written instructions that he – David – had received from Hashem through prophecy.,
The Talmud does not comment on the passage or explain its relevance to the paradox. However, Rav Yitzchak Zev Soloveitchik – the GRI”Z – offers an interesting explanation of the Talmud’s comments. He suggests that although it is virtually impossible to make a measurement with exact precision, it is innately impossible. In attempting to make a precise measurement we are typically defeated by the imprecision of our measuring tools and the limitations of the human senses. However, if these limitations can be overcome, a precise measurement is possible. Based on this assertion, the GRI”Z explains the Talmud’s comments. David told Shlomo that he had received through prophecy exact specifications for the Bait HaMikdash. He assured Shlomo that the building of the Bait HaMikdash would be guided by the same Divine inspiration. Through this inspiration they would achieve a level of perfect precision not normally possible.
According to the GRI”Z, the Talmud is suggesting that even the Sages that maintain that exact precision is normally impossible to achieve would acknowledge that the Mishcan and its components were built with exact precision. They too were guided in their efforts by Divine inspiration. This guidance enabled them to achieve a level of precision that is normally not attainable.
We can now understand Rabbaynu Yonatan ben Uziel’s comments on our passage. The crafts-people who build the Mishcan required the spirit of prophecy in order to complete their task. This spirit of prophecy guided them and assured their success in achieving the precise specifications required for the Mishcan and its components.
 Rabbaynu Yonatan ben Uzial, Tirgum on Sefer Shemot 35:21.  Mesechet Succah 15a – 15b.  Mesechet Bechorot 17b.  Sefer Divrei HaYamim I, 28:19.  Mesechet Bechorot 17b.  Rav Y. Hershkowitz, Netivit Rabotaynu (Jerusalem 5762), volume 1, pp. 415-416.