וַיִּפְרֹשׂ אֶת הָאֹהֶל עַל הַמִּשְׁכָּן וַיָּשֶׂם אֶת מִכְסֵה הָאֹהֶל עָלָיו מִלְמָעְלָה כַּאֲשֶׁר צִוָּה יְדֹוָד אֶת משֶׁה: (שמות מ:יט)
“And he (Moshe) spread the covering on the Mishkan and he put another covering over the first covering just like Hashem commanded him,” (Shemos 40:19).
It is written in the Gemara Nedarim (38A), “Hashem only rests His Shechina on a person who is strong, wealthy, wise and humble and Moshe, who is the model of a perfect prophet, had all of these characteristics. The Gemara initially brings a proof that Moshe was strong from the pasuk (19): “Vayifros Moshe ess haohel al Hamishkan—And Moshe spread a covering on the Mishkan,” with the following logic, since we know that the Mishkan was 10 ammos tall (between 4.8 and 5.7 meter or between 15 feet and 10 inches and 20 feet tall) and we learnt that Moshe spread it by himself, it must be then that Moshe was tall. If he was tall, then he must have also been strong. The Gemara rejects this proof because the fact that Moshe was tall is no proof that he was also strong. It might be that he was only tall, but not strong. The Gemara, therefore, concludes that the proof is from the fact that he grabbed and threw the tablets on which the 10 commandments were written.
The Maharsha quotes the Rosh who asks: “Why did the Gemara bring a proof from pasuk 19, ‘And he (Moshe) spread the cover over the Mishkan’ and not from the previous pasuk (18), ‘And Moshe erected the Mishkan… and he stood up the beams …?” Beams are heavier than the goat skins that covered the Mishkan. This is a much better proof because the Gemara cannot discard this proof and say that Moshe was only tall; like it rejected the proof from the fact that Moshe spread the goat skin covering because only a very strong person can pick up such huge beams!
Zera Shimshon answers: The Gemara’s proof is really from the fact that Moshe stood up the beams and the Gemara only quoted the fact that Moshe spread the goat skin covering because without this pasuk there is no proof that Moshe was strong!
If only for the fact that Moshe stood up the beams, we could still think that Moshe really was not strong at all and he was able to stand up those huge beams only because Hashem made a miracle for him. The reason Hashem made this miracle was because Moshe had no part in the building of the Mishkan and Hashem wanted him to also take part. This is similar to what happened with the heads of the tribes. They didn’t donate anything to the building of the Mishkan because they were waiting to see what was missing after all of Bnei Yisroel had brought their donation. In the end, Bnei Yisroel were very generous and there was nothing left for them to bring. Hashem, therefore, showered down precious stones from the sky to the leaders of the tribes in order for them to contribute and take part in the building of the Mishkan.
To eliminate this possibility, the Gemara quotes the pasuk, “And he (Moshe) spread the covering over the Mishkan,” to prove that Moshe already took part of the erection of the Mishkan and, therefore, there was no need for Hashem to make a miracle for him to be part of it and it must be because he was strong!
(What I still don’t understand is that Zera Shimshon’s answer is too good! The Gemara, eventually, rejects this proof that Moshe was strong because even if it is true that Moshe was tall, maybe he was weak. I am having a problem as to how to understand how this invalidates the proof. According to Zera Shimshon, if he was only tall but weak and was able to spread the goat skin on the Mishkan because you don’t need to be strong to do this, he still would have to be very strong to lift the beams of the Mishkan. Therefore, there still is solid proof that Moshe was strong from the fact that he lifted the beams. So why did the Gemara reject this proof and had to bring a proof from the fact that Moshe picked up and threw the tablets of the 10 commandments? Sh. P.)