with forty silver bases under the twenty frames—two bases for each frame, one under each tenon.
Very particular directions are here given about the boards of the tabernacle, which were to bear up the curtains, as the stakes of a tent which had need to be strong, Isa 54:2. These boards had tenons which fell into the mortises that were made for them in silver bases. God took care to have every thing strong, as well as fine, in his tabernacle.
Commenting on Exodus 26:15-30
And for the second side of the tabernacle the north side,.... The direction of the tabernacle was east and west; at the east end was the entrance into the holy place, and at the west end the holy of holies; and the two sides were north and south; and as on the south side, so on the north there shall be twenty boards: just the...
Exo 26:18-21 Twenty of these boards were to be prepared for the side of the dwelling that was turned towards the south, and forty sockets (אדנים foundations, Job 38:6) or bases for the pegs, i.e., to put the pegs of the boards into, that the boards might stand upright; and the same number of boards and sockets for the north side.
Commenting on Exodus 26:18-21