Exodus 26:17

Two tenons shall there be on one board,.... Every board was to be so cut and shaped at the lower end of it, as to have, as it were, "two hands" r, 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.

r שתי ידות "duae manus", Montanus.