Made out of Acacia Wood: Parshat Terumah
(י) וְעָשׂ֥וּ אֲר֖וֹן עֲצֵ֣י שִׁטִּ֑ים אַמָּתַ֨יִם וָחֵ֜צִי אָרְכּ֗וֹ וְאַמָּ֤ה וָחֵ֙צִי֙ רָחְבּ֔וֹ וְאַמָּ֥ה וָחֵ֖צִי קֹמָתֽוֹ׃

(10) They shall make an ark of acacia wood, two and a half cubits long, a cubit and a half wide, and a cubit and a half high.

(א) ועשו ארון. בכלהו כתיב ועשית וכאן כתיב ועשו לפי שהכל חייבין להתעסק בו מפני כבוד התורה שבתוכו וק"ו לתלמידי חכמים שבני עירם מצווים לעשות מלאכתן כדי לכבדם והכי איתא ביומא פרק בא לו ועשו ארון מכאן לת"ח וכו'.

(1) ועשו ארון, “they are to construct an Ark;” it is noteworthy that the Torah, in these instructions about construction of the furnishings of the Tabernacle, addresses the artisans as individuals, i.e. ועשית, you, the individual, shall construct, whereas when speaking of the Holy Ark, it uses the impersonal plural of ועשו, “they shall construct.” The reason is that seeing that the Holy Ark, repository of the Tablets and the original Torah scroll, is to be something that every Israelite must feel that he had a part in making its construction possible. (Sh’mot Rabbah 34,2).

(ב) מבית ומחוץ תצפנו. אמר רבא כל ת"ח שאין תוכו כברו אינו תלמיד חכם. ועוד צוה הקב"ה לכל ישראל להתעסק בו כדי שיהו כלן מקבלין שכר התורה המונחת בו שם:

(2) מבית ומחוץ תצפנו, “you are to overlay it both from the inside and from the outside. The famous Talmudic scholar Rava, derives from this phrasing that a Torah scholar, in order to deserve that title, must demonstrate that he is on the inside just as pure and faithful as what he projects to be on the outside to people he comes into contact with. Furthermore, the use of the impersonal plural “they” in our verse is an instruction to each Israelite to preoccupy himself with the study of Torah so that he can qualify for the reward in store for people doing so.

(א)וַיַּעַשׂ בְּצַלְאֵל אֶת הָאָרֹן עֲצֵי שִׁטִּים. לְפִי שֶׁגָּלוּי הָיָה לִפְנֵי מִי שֶׁאָמַר וְהָיָה הָעוֹלָם, שֶׁיִּשְׂרָאֵל חוֹטְאִים בַּשִּׁטִּים. לְכָךְ תִּקֵּן לָהֶם הַקָּדוֹשׁ בָּרוּךְ הוּא שִׁטִּים, לְכַפֵּר עַל מַעֲשֵׂה שִׁטִּים. וַיְצַף אֹתוֹ זָהָב טָהוֹר, אֵלּוּ הַתַּלְמִידִים בְּנֵי תוֹרָה. כִּי כְמוֹ שֶׁמִּתְכַּבֵּד הָעֵץ בַּזָּהָב, יוֹתֵר וְיוֹתֵר מִתְכַּבְּדִין הַתַּלְמִידִים בַּתּוֹרָה, שֶׁהִיא בְּתוֹךְ לִבָּם. וּכְמוֹ שֶׁיֹּאמְרוּ אֲנָשִׁים זָהָב טָהוֹר, כָּךְ מְטַהֵר הַתּוֹרָה לִבָּן וְכִלְיוֹתָן שֶׁל תַּלְמִידֵי חֲכָמִים. שֶׁכָּךְ כְּתִיב: הַנֶּחֱמָדִים מִזָּהָב וּמִפָּז רָב (תהלים יט, יא). וַיַּעַשׂ בְּצַלְאֵל. אָנוּ מוֹצְאִין כְּשֶׁאָמַר הַקָּדוֹשׁ בָּרוּךְ הוּא לְמֹשֶׁה לַעֲשׂוֹת אֶת הַמִּשְׁכָּן, אָמַר לוֹ עַל כָּל דָּבָר וְדָבָר, וְעָשִׂיתָ. וְעַל הָאָרוֹן אָמַר, וְעָשׂוּ (שמות כה, י). לָמָּה, אֶלָּא שֶׁצִּוָּה הַקָּדוֹשׁ בָּרוּךְ הוּא לַעֲשׂוֹתוֹ לְכָל יִשְׂרָאֵל, שֶׁלֹּא יְהֵא לְאֶחָד מֵהֶם פִּתְחוֹן פֶּה עַל חֲבֵרוֹ לוֹמַר, שֶׁאֲנִי נָתַתִּי הַרְבֵּה בָּאָרוֹן לְפִיכָךְ אֲנִי לוֹמֵד הַרְבֵּה וַאֲנִי יֶשׁ לִי בוֹ יוֹתֵר מִמְּךָ וְאַתָּה לֹא נָתַתָּ בָּאָרוֹן כְּלוּם אֶלָּא מְעַט לְפִיכָךְ אֵין לְךָ חֵלֶק בַּתּוֹרָה. וּלְכָךְ נִמְשְׁלָה הַתּוֹרָה לַמַּיִם, שֶׁנֶּאֱמַר: הוֹי כָּל צָמֵא לְכוּ לַמַּיִם (ישעיה נה, א). כְּשֵׁם שֶׁאֵין אָדָם מִתְבַּיֵּשׁ לוֹמַר לַחֲבֵרוֹ הַשְׁקֵנִי מַיִם, כָּךְ לֹא יִתְבַּיֵּשׁ לוֹמַר לְקָטָן מִמֶּנּוּ לַמְּדֵנִי תוֹרָה, לַמְּדֵנִי דָבָר זֶה. וּכְשֵׁם שֶׁהַמַּיִם כָּל הָרוֹצֶה לִשְׁתּוֹת יִשְׁתֶּה בְּלֹא מְחִיר, כָּךְ כָּל הָרוֹצֶה לִלְמֹד תּוֹרָה, לוֹמֵד בְּלֹא מְחִיר וּבְלֹא כֶסֶף, שֶׁנֶּאֱמַר: לְכוּ שִׁבְרוּ בְּלוֹא כֶסֶף וּבְלוֹא מְחִיר (ישעיה נה, א).

(1) And Bezalel made the ark of acacia-wood (Exod. 37:1). Because it was known to The-One-who-spoke-and-the-world-came into-being that Israel will sin at Shittim, the Holy Blessed One, prepared shittim (acacia-wood) so that they might atone for what happened at Shittim (see Numbers 25). In building the ark of shittim (acacia wood) they were able to obtain forgiveness for the sins perpetrated at Shittim. And he overlaid it with pure gold (ibid., v. 2). This alludes to the students of the Torah, for just as the wood was greatly adorned by the gold that overlaid it, so the students of the Torah are adorned by the Torah within their hearts. Just as men speak of pure gold, so the Torah purifies the heart and the kidneys of the scholar, as it is written: More to be desired are they than gold, yea, than much fine gold (Ps. 19:11). And Bezalel made the ark. We find that when the Holy One, blessed be he, told Moses to construct the Tabernacle, He described every detail to him, saying: Thou shalt do, but with reference to the ark, He said simply: Make Me. Why? The Holy One, blessed be He, commanded all the Israelites to make it, so that not one of them would be able to humiliate his fellow Israelite by saying: “I contributed more for the building of the ark than you, therefore I am more learned and have a greater right to it than you do. And since you contributed little to the ark, you will have no portion in the Torah.” That is why the Torah is likened to water, as it is said: Ho, everyone that thirsteth, come you for water (Isa. 55:1). Just as no one should be ashamed to say to his companion: “Give me a drink of water,” no one should be ashamed to say to a person younger than himself: “Teach me the law, instruct me in this matter.” And just as one who desires to drink should be able to drink without cost, so all who desire to learn the law should be able to learn without cost and without price, as it is said: Yea, come without money and without price (ibid.).

(כג) וְעָשִׂ֥יתָ שֻׁלְחָ֖ן עֲצֵ֣י שִׁטִּ֑ים אַמָּתַ֤יִם אָרְכּוֹ֙ וְאַמָּ֣ה רָחְבּ֔וֹ וְאַמָּ֥ה וָחֵ֖צִי קֹמָתֽוֹ׃
(23) You shall make a table of acacia wood, two cubits long, one cubit wide, and a cubit and a half high.

(1) ועשית שלחן, the table represented the kings of Israel who entertain the Torah scholars at their table... The Torah, in describing the table in the Tabernacle as overlaid with gold, illustrates that the function of Royalty was primarily to make a great impression on the outside world. After Samuel had told Saul that he would be replaced as king by someone more worthy, Saul still begged the prophet to honour him at least in public as he wanted to maintain the appearance although he realised that this was no longer his position. (compare Samuel I 15,30).
The reason that the length of the table was 21/2 cubits was in order to symbolize two requirements which every king has to meet. 1) He must be competent in meting out justice; 2) he must be competent in waging war. This is what the people had told Samuel when they asked him to appoint a king for them (Samuel I 8:20).

...All the details that the Torah writes about in connection with all the vessels of the Tabernacle contain similar allusions of a moral-ethical nature. The Ark represents the righteous people. The table corresponds to the kings of Israel. The Menorah corresponds to the scholars of Israel. The golden altar corresponds to the priests, whereas the copper altar corresponds to the people at large.

(א) ועשית שלחן. כבר נתבאר כי הארון הצורך גדול היה להיות לוחות העדות מונחים בתוכו, והכפורת גם כן הוא הכסוי אשר עליו כמו (בראשית ו) וכפרת אותה שתרגומו ותחפי יתה, והכרובים שהיו מן הכפורת להורות על מציאות המלאכים, אבל השלחן מה היה משמש ומה צורך היה במשכן ובמקדש לעשות בהם שלחן.

(1) ועשית שלחן, “you are to construct a table.” It has already been demonstrated that there was a real need for the Ark seeing that it served to house the Tablets. The kapporet was also essential as it served as the lid for the Ark...The cherubs on top of the kapporet were needed to demonstrate that there are such beings as angels. This leaves the question of what need did the presence of the table actually fill? ...In fact, the table (in each man’s house) symbolises the altar, the instrument through which man is able to achieve atonement for his errors. The bread on the table is considered as a surrogate for animal sacrifice on the altar provided man is generous and shares his blessings (food, etc.) with the poor. This is the deeper meaning of what the sages said (Berachot 55) when they commented on Ezekiel 41:22 “and the altar, a wooden block, three cubits high,.....and He said to me: ‘this is the table before God.” The remarkable thing in that vision is that it commenced with the altar and concluded with the table. The message to Ezekiel was that as long as the Temple was standing and the altar was functioning, man’s atonement was achieved through the sacrifices offered on the altar. When there is no altar upon which to offer sacrifices, man must achieve his atonement by means of his table. ...(5) It became an accepted practice amongst the pious Jews of France to construct their caskets out of the wood of their tables in order to demonstrate the idea that their table become the means of their atonement just as death is the means to achieve our ultimate atonement. It also was to signify that man does not take with him any of the material things he enjoyed on earth. The only thing he can take with him is the evidence of the charitable deeds he performed while alive. The table was a prime symbol of such charitable deeds. This is also why the sages (Berachot 54) said that he who spends a long time over his meal will have his life extended.” [The idea is that the poor may come to his door while he is still eating and they will be invited to share. Ed.]

(טו) וְעָשִׂ֥יתָ אֶת־הַקְּרָשִׁ֖ים לַמִּשְׁכָּ֑ן עֲצֵ֥י שִׁטִּ֖ים עֹמְדִֽים׃

(15) You shall make the planks for the Tabernacle of acacia wood, upright.

(א) ועשית את הקרשים. הָיָה לוֹ לוֹמַר וְעָשִׂיתָ קְרָשִׁים, כְּמוֹ שֶׁנֶּאֱמַר בְּכָל דָּבָר וְדָבָר, מַהוּ הַקְּרָשִׁים? מֵאוֹתָן הָעוֹמְדִין וּמְיוּחָדִין לָכַךְ; יַעֲקֹב אָבִינוּ נָטַע אֲרָזִים בְּמִצְרַיִם, וּכְשֶׁמֵּת צִוָּה לְבָנָיו לְהַעֲלוֹתָם עִמָּהֶם כְּשֶׁיֵּצְאוּ מִמִּצְרַיִם, וְאָמַר לָהֶם שֶׁעָתִיד הַקָּבָּ"ה לְצַוּוֹת אוֹתָן לַעֲשׂוֹת מִשְׁכָּן בַּמִּדְבָּר מֵעֲצֵי שִׁטִּים, רְאוּ שֶׁיִּהְיוּ מְזֻמָּנִים בְּיֶדְכֶם; הוּא שֶׁיִּסֵּד הַבַּבְלִי בְּפִּיּוּט שֶׁלּוֹ, "טָס מַטָּע מְזוֹרָזִים קוֹרוֹת בָּתֵּינוּ אֲרָזִים", שֶׁנִּזְדָּרְזוּ לִהְיוֹת מוּכָנִים בְּיָדָם מִקּוֹדֶם לָכֵן:

(1) ועשית את הקרשים AND THOU SHALT MAKE THE BOARDS — It should be said: “Thou shalt make boards” (without the definite article), the same form which is used of each of the other things (in the Tabernacle)! What is the force of the term, “the boards?” It speaks of those boards that already existed as being designated for that purpose.

The Book of Legends 5:70

Where did the boards come from? Jacob our father planted them. When he came down to Egypt he said to his sons: My sons! You are destined to be redeemed from here, and when you are redeemed the Holy One will tell you to make a Tabernacle for Him. Rise up and plant cedars now, so that when God tells you to make a Tabernacle, these cedars will be on hand. So Jacob's sons set to planting, doing just what he had told them.

(א) עצי שטים עומדים. פשטיה שלא תקח מן הנפולים והנקצצין מימים רבים שכבר נרקבו אלא מן העומדים בקומתם. ד"א עומדים שהן עומדים לעולם ועדיין הם קיימים ונגנזים:

(1) עצי שטים עומדים, “made of acacia wood standing upright.” One interpretation of the word עומדים, is that they were taken from trees which up to that time had been standing rooted in the earth, i.e. they had not had time to dry out or to begin to rot. An alternate explanation for the word עומדים would be that the boards remained in their prime condition forever.

אמר רבי חמא ברבי חנינא מאי דכתיב (שמות כו, טו) עצי שטים עומדים שעומדים דרך גדילתן דבר אחר עומדים שמעמידין את צפויין ד"א עומדים שמא תאמר אבד סברן ובטל סכויין ת"ל עומדים שעומדין לעולם ולעולמים

The Gemara cites other statements concerning the ark. Rabbi Ḥama, son of Rabbi Ḥanina, said: What is the meaning of that which is written: “And you shall make the boards for the Tabernacle of acacia wood, standing” (Exodus 26:15)? This verse teaches that the boards of wood used for the Tabernacle should stand in the same direction in which they grew from the ground as a tree. Alternatively, “standing” means that they supported their gold plating and prevented it from falling. Alternatively, “standing” is written to hint at the following: Perhaps you will say that now that the Tabernacle is no longer in use, their hope is lost and their chance is abandoned, and after being stored away the boards will no longer return to use. Therefore, the verse states “standing” to indicate that they stand forever and ever.