The verses at the beginning of the sidrah list in exhaustive detail the various materials that were donated and used for the Mishkan (the Tabernacle), from gold and silver all the way through to the shoham stones and stones for settings for the ephod and the breastplate.
The Or Hachaim (Rabbi Chaim ben Moses ibn Attar) observes that the list of materials seems to be presented in descending order of value, yet the last two items, the shoham and other precious stones, seem out of position since they were the most precious and therefore should have been mentioned at the beginning of the list.
The princes of the tribes, when solicited to donate to the Tabernacle, responded by saying that everyone else should be asked to donate first and then they would make up any deficit remaining at the end of the building campaign. However, since the general populace contributed everything that was required for the building, the princes, as a result, gave precious stones that were not part of the main building fund.
On the surface this seems a most magnanimous gesture since they made a far greater contribution than the general masses. However the Torahwas critical of their laziness in contributing. What was wrong with their approach?
The Or Hachaim explains that the princes should have realised that in building the Mishkan, there could be no such thing as a deficit. A deficit implies a lack, something missing. But God did not need our money in the first place. He merely gave us the opportunity to earn the merit of participating in this mitzvah.
We all are willing to be asked to contribute time and resources as a last port of call, but perhaps the lesson we should learn from the subtle criticism of the princes is that we should aim to be first in offering rather than last.