Exodus 26:20

And thou shalt make the boards for the tabernacle, twenty boards on the south side southward.

And thou shalt make forty sockets of silver under the twenty boards; two sockets under one board for his two tenons, and two sockets under another board for his two tenons.

And their forty sockets of silver; two sockets under one board, and two sockets under another board.

And for the sides of the tabernacle westward thou shalt make six boards.