For the second side of the tabernacle, the north side, make twenty frames
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 their forty sockets of silver,.... 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. And their forty sockets of silver,....
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