This week we are privileged to be reading the portion of Terumah. This portion begins with G-d's command to Moshe to tell the Jews to take contributions from everyone whose "heart motivates him"...
The Jews were to contribute 13 different items for the Mishkan, a dwelling for G-d. In the Mishkan, there would be a constant feeling of G-d's Presence.
All the articles of the Mishkan, the Aron (ark), Shulchan (table), Menorah, Mizbeiach (altar) and so on, needed to be built with exact measurements and specifications, as the Torah describes.
In Shmos 26/30 Hashem tell Moshe "you shall erect the mishkan according to its manner, as you have been shown on the mountain (sinai). The Torah repeats several times similar phrases regarding articles of the mishkan that it should be made as you were shown on the mountain.
We need to understand, what is this referring to ? What's the reference to the mountain ?
To understand this, perhaps we can benefit from an explanation given regarding Kabolas Hatorah. The medrash teaches us, that G-d approached all the nations, whether they would like to accept the Torah. Upon their question, as to what is written in the Torah ? G-d replied to each nation just that which was against his nature thou shall not steal, thou shall not kill etc..... Naturally they were not willing to accept something which would require a lot of work (breaking their nature). The nations might however argue, that had G-d put the Jews in same situation they may have refused as well. This is why G-d gave the mitzvah of hagbeil. The Jews were commanded to create a boarder around Mount Sinai, Moshe and Aharon go up and the rest of the nation must be restricted to an exact area not even centimeter closer than allowed. The nature of being fenced in and LIMITED, this is not characteristic for a Jew. However when they were commanded to do so they accepted with pleasure to do G-d's will.
Similarly, when it comes to the mishkan, one might think I'll build a couple of meters bigger, what would be so terrible ? That's why G-d told Moshe "as you were shown at the mountain", to say that when G-d commands limitations, we accept it precisely according to His will. Just as we did at Mount Sinai, so too at the Mishkan, when limitation is required, we accept it despite our possible desire to build bigger.
In conclusion what we learn from this is that sometimes being limited may bring about unlimited opportunities. But we must remember that this is only applicable when G-d requires that of us.