Exodus 26:21

“And their forty sockets of silver, etc.] answerable to the twenty boards, for their two tenons to be placed in as in mortises: two sockets under one board, and two sockets under another board; and so under all the boards on the north side as on the south.”

“(Compare Exodus 36:8-33.) The tabernacle was to comprise three main parts, the tabernacle Exodus 26:1-6, more strictly so-called, its tent Exodus 26:7-13, and its covering Exodus 26:14 (Compare Exodus 35:11; Exodus 39:33-34; Exodus 40:19, Exodus 40:34; Numbers 3:25, etc.). These parts are very clearly distinguished in the Hebrew, but they are confounded in many places of the English Version (see Exodus 26:7, Exodus 26:9, etc.). The tabernacle itself was to consist of curtains of fine linen woven with colored figures of cherubim, and a structure of boards which was to contain the holy place and the most holy place; the tent was to be a true tent of goats’ hair cloth to contain and shelter the…”

“two sockets under one board: Exo 26:19 Exodus 26:23”