John Gill Bible Commentary

And thou shalt make bars of shittim wood, Which being put into rings or staples of gold, kept the boards tight, close, and firm together: five for the boards of the one side of the tabernacle: for instance, the south side; four of these were placed, two at the upper end of the boards, and two at the lower end, and the fifth in the middle, particularly taken notice of, Exo 26:28, how long these bars were it is not said, but it is reasonable to conclude that they reached the length of the tabernacle, which was thirty cubits; and as it was not easy to get bars of such a length, the notion of Josephus (u) perhaps, may be right, that each two consisted of divers parts which joined one another, the head of one entering into the hollow of the other and as he supposes they were five cubits long, a row of them must have six parts, which went along the sides, north and south, and the west end two, which was but ten cubits. (u) Ut supra. (Antiqu. l. 3. c. 6. sect. 3.)