Exodus 26:18

“And thou shalt make the boards for the tabernacle, etc.] As in the manner before described, so in number as follows: twenty boards on the south side southward; which being a cubit and a half broad, made the length of the tabernacle fifteen yards according to the common account; but if these were cubits of twenty one inches, then its length was much greater.”

“(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…”

“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. תּימנה, "southward," is added to נגבּה לפאת in Exo 26:18, to give a clearer definition of negeb, which primarily means the dry, and then the country to the south; an evident proof that at that time negeb was not established as a geographical term for the south, and therefore that it was not written here by a Palestinian, as Knobel supposes, but by Moses in the desert. The form…”