Rashi's Explanation
In this week's Torah portion, Terumah, Hashem commands us to build the Mishkan. He commands us to "separate an offering," which should be "taken for Me." He then commands us to take specific items used in the building of the Mishkan. Hashem told us to bring gold, silver, copper, blue, purple, crimson wool, linen, goat hair, ram's skins dyed red, and tachash skins. Among the other offerings, He told us to bring acacia wood. Rashi cites the verse "and acacia wood" and explains it. "Where did they get these (trees) in the desert? Rabbi Tanchumah explained that our father Yaakov foresaw, by prophecy, that the Jews would build a Mishkan in the desert, so he brought cedars to Egypt and planted them. He commanded his descendants to take the trees with them when they left Egypt." Rashi seems to be quoting Rabbi Tanchumah to explain how the Jews got lumber in a desert.
Difficulties in Understanding Rashi
Rabbi Tanchumah's teaching is a Midrash, which seemingly has no place in Peshat! Why does Rabbi Tanchumah need to say that Yaakov brought trees from Israel over 200 years earlier to have wood to donate for the Mishkan? There are other ways we could have acquired wood; for example, we could have purchased wood from neighboring nations. The Ibn Ezra and the commentary on the Torah by the Baalei Tosfos offer explanations far closer to Peshat. They both say there was a forest near Mount Sinai from which we took the wood.
Additionally, it's not typical for Rashi to use an expression such as "Rabbi Tanchumah explained." Usually, Rashi would say something to the effect of "We find in the Midrash Tanchumah," or, as he often did, he would state the explanation and, at its conclusion, cite the source. What is the reason for Rashi's stylistic change?
Moreover, it does not seem true that "Rabbi Tanchumah explained," as Rashi states. He is not explaining the verse; he is merely teaching us something that answers a question that arises from the verse.
