Exodus 26:17

“Two tenons shall there be on one board, etc.] Every board was to be so cut and shaped at the lower end of it, as to have, as it were, “two hands” f788, as in the original, to enter into, lay hold on, and fasten in mortises: set in order one against another; at a proper distance from each other, as the rounds of a ladder: thus shalt thou make for all the boards of the tabernacle; everyone was to have two tenons.”

“(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…”

“tenons: Heb. hands, Exo 26:19, Exo 36:22, Exo 36:24 Exodus 26:19”

“Every board was to have two ידות (lit., hands or holders) to hold them upright, pegs therefore; and they were to be "bound to one another" (משׁלּב, from שׁלב in Chald. to connect, hence שׁלבּים in Kg1 7:28, the corner plates that hold together the four sides of a chest), not "pegged into one another," but joined together by a fastening dovetailed into the pegs, by which the latter were fastened still more firmly to the boards, and therefore had greater holding power than if each one had been simply sunk into the edge of the board. Exodus 26:18”