l'ilui nishmat R' Avraham ben Yona Ya'akov

“they shall make the Aron (ark)” (25; 10)
Regarding all of the other items in the mishkan the verse says ‘you shall make’, directing the instruction to Moshe. Only with the Aron does it state ‘they shall make’, directed at all of Israel. The Aron represents Torah, as it contains within it the two stone tablets. The verse states “You shall place the Edut in the Aron” (verse 16) and edut refers to the tablets of testimony. Therefore we can say that the verse uses the third person plural to teach us that when it comes to supporting Torah everyone is equally obligated, rich or poor.
This is implicit in the Yerushalmi (Sotah 7; 4) where it expounds the verse (Devarim 26; 26) “Cursed is the one who does not uphold the words of the Torah”. This means that even one who has not learnt and not taught, but strengthens and supports those who learn Torah, is included in the blessing of “that upholds the Torah”. (The blessings in that parsha are the inverse language of the curses). This is clearly said to everybody, as it states, ‘even someone who has not learnt and not taught’. Even a person who has no direct connection to learning or teaching Torah is still obligated to uphold the Torah.
The reason for this is clear, based on the verse in Mishlei (3; 18) “It is a tree of life to those that uphold it”. Every person needs life, wise or foolish, rich or poor. Therefore the verse is teaching us that everyone must support Torah learning.

“They shall make an Aron of cedar wood, two and a half amot (amataim vachetzi) is its length” (25; 10)
The Talmud (Sanhedrin 29a) learns from here that anyone who adds really subtracts. Rashi explains that if you would remove the aleph from amataim (two amot) it would read mataim, meaning two hundred. By adding the aleph you really subtract from the total number and make it only two amot.
But Rashi’s explanation is difficult to understand. If the Torah would have only written mataim we wouldn’t know which measure it was using. It may have meant 200 amot, or 200 tefachim or 200 etzbaot (or any other measure). Whereas the word amataim speaks specifically about the length of two amot.
In the Torah Temima we gave a different explanation from one of the Rabbis of the Talmud there. When it says ‘anyone who adds, subtracts’ it refers not to the aleph, but to the vav of vachetz (and half). If it would have left out that letter the verse would have read ‘two amot is half its length’ which would imply a total length of four amot. By adding the vav the Torah teaches us that the length is only two amot, and therefore is subtracting. Even though in the Torah Temima we challenged this explanation, it nevertheless seems to be the most correct reading.

(editor’s note: in the Torah Temima he cites this in the name of the Rashash who attributes it anonymously. I also saw this explanation in the sefer Kol Eliyahu by the Vilna Gaon).