Thou shalt make boards - These formed what might be called the walls of the tabernacle, and were made of shittim wood, the acacia Nilotica, which Dr. Shaw says grows here in abundance. To have worked the acacia into these boards or planks, the Israelites must have had sawyers, joiners, etc., among them; but how they got the tools is a question. But as the Israelites were the general workmen of Egypt, and were brought up to every kind of trade for the service of their oppressors, we may naturally suppose that every artificer brought off some of his tools with him. For though it is not at all likely that they had any armor or defensive weapons in their power, yet for the reason above assigned they must have had the implements which were requisite for their respective trades.

And thou shalt make the boards for the tabernacle,.... Which were the pillars and supports, and properly the walls of it, which gave it its firmness and security, or otherwise the curtains would have been blown about by every wind: they were to be made
of shittim wood standing up; just as they grew, as a Jewish writer observes (p); these planks or boards were not to be laid along the lengthways of them, but to be set upright; and may denote such who are pillars in the house of God, and are to be upright both in heart and conversation, both ministers and private members; and indeed the church itself is the pillar and ground of truth, Galatians 2:9.
(p) Bartenora in Misn. Succa, c. 3. sect. 14.

The sockets of silver each weighed about 115 pounds; they were placed in rows on the ground. In every pair of these sockets, a strong board of shittim-wood, covered with plates of gold, was fitted by mortises and tenons. Thus walls were formed for the two sides, and for the west end. The wall was further held together by bars, which passed through rings of gold. Over this the curtains were spread. Though movable, it was strong and firm. The materials were very costly. In all this it was a type of the church of God, built upon the foundation of the apostles and prophets, Jesus Christ himself being the chief Corner-stone, Ephesians 2:20, Ephesians 2:21.

thou shalt make boards . . . rear up the tabernacle according to the fashion . . . which was showed thee--The tabernacle, from its name as well as from its general appearance and arrangements, was a tent; but from the description given in these verses, the boards that formed its walls, the five (cross) bars that strengthened them, and the middle bar that "reached from end to end," and gave it solidity and compactness, it was evidently a more substantial fabric than a light and fragile tent, probably on account of the weight of its various coverings as well as for the protection of its precious furniture.

The wooden framework. - Exodus 26:15, Exodus 26:16. The boards for the dwelling were to be made "of acacia-wood standing," i.e., so that they could stand upright; each ten cubits long and one and a half broad. The thickness is not given; and if, on the one hand, we are not to imagine them too thin, as Josephus does, for example, who says they were only four fingers thick (Ant. iii. 6, 3), we have still less reason for following Rashi, Lund, Bhr and others, who suppose them to have been a cubit in thickness, thus making simple boards into colossal blocks, such as could neither have been cut from acacia-trees, nor carried upon desert roads.
(Note: Kamphausen (Stud. und Krit. 1859, p. 117) appeals to Bhr's Symbolik 1, p. 261-2, and Knobel, Exod. p. 261, in support of the opinion, that at any rate formerly there were genuine acacias of such size and strength, that beams could have been cut from them a cubit and a half broad and a cubit thick; but we look in vain to either of these writings for such authority as will establish this fact. Expressions like those of Jerome and Hasselquist, viz., grandes arbores and arbos ingens ramosissima, are far too indefinite. It is true that, according to Abdullatif, the Sont is "a very large tree," but he gives a quotation from Dinuri, in which it is merely spoken of as "a tree of the size of a nut-tree." See the passages cited in Rosenmller's bibl. Althk. iv. 1, p. 278, Not. 7, where we find the following remark of Wesling on Prosper. Alpin. de plantis Aeg.: Caudicem non raro ampliorem deprehendi, quam ut brachio meo circumdari possit. Even the statement of Theophrast (hist. plant. 4, 3), to the effect that rafters are cut from these trees 12 cubits long (δωδεκάπηχυς ἐρέψιμος ὕλη), is no proof that they were beams a cubit and a half broad and a cubit thick. And even if there had been trees of this size in the peninsula of Sinai in Moses' time, a beam of such dimensions, according to Kamphausen's calculation, which is by no means too high, would have weighed more than twelve cwt. And certainly the Israelites could never have carried beams of this weight with them through the desert; for the waggons needed would have been such as could never be used where there are no beaten roads.)
To obtain boards of the required breadth, to or three planks were no doubt joined together according to the size of the trees.

Very particular directions are here given about the boards of the tabernacle, which were to bear up the curtains. These had tenons which fell into the mortaises that were made for them in silver bases. The boards were coupled together with gold rings at top and bottom, and kept firm with bars that run through golden staples in every board. Thus every thing in the tabernacle was very splendid, agreeable to that infant state of the church, when such things were proper to possess the minds of the worshippers with a reverence of the divine glory. In allusion to this, the new Jerusalem is said to be of pure gold, Revelation 21:18. But the builders of the gospel church said, Silver and gold have we none; and yet the glory of their building far exceeded that of the tabernacle.