Exodus 26:24-28

They shall be double beneath, and together they shall be complete to its top to the first ring; this is how it shall be with both of them: they shall form the two corners.

And there shall be eight boards with their bases of silver, sixteen bases; two bases under one board and two bases under another board.

“Then you shall make bars of acacia wood, five for the boards of one side of the tabernacle,

and five bars for the boards of the other side of the tabernacle, and five bars for the boards of the side of the tabernacle for the back side to the west.

The middle bar in the center of the boards shall pass through from end to end.