Commentary for Exodus 26:25

והיו שמנה קרשים AND THEY SHALL BE EIGHT BOARDS — These are the same boards mentioned above (vv. 22—23): “Thou shalt make six boards” … “and two boards shalt thou make for the corners”; consequently there were eight boards in the western row. The following is stated in that Mishna (paragraph) in the Boraitha dealing with “The structure of the Tabernacle” which treats of the method of arranging the boards of the Tabernacle: they made the sockets hollow, and cut away the board at the bottom, a quarter of its width being left on one side and a quarter on the other side, the portion cut away in the middle being one half its width. Thus they made for it (the board) two tenons like two חמוקין — I think the correct reading is, “like two חווקין” i. e. like two rungs of a ladder set at some distance one from the other. These were planed down so as to fix into the hollow of the socket just as a rung which is fixed into the hole in the ladder’s upright. This is the meaning of משלבות, viz., made like a rung (שליבה). They fixed them (the two tenons) into the two sockets as it says, (v. 19) “two sockets [under one board for its two tenons] and two sockets [under another board for its two tenons]”. They cut out the board at the top a finger breadth on this side and a finger breadth on that side and put them (two semicircular projecting pieces on two adjacent boards) into one golden ring in order that they (the boards) should not fall apart, as it says, “and they shall be coupled together beneath, [and they shall be coupled together above].” Thus the Mishna; its explanation I have set forth above following the order of the verses.

והיו שמונה קרשים, “there shall be eight beams, etc.” Two of the eight beams overlapped with the beams forming the long sides of the Tabernacle, one at the southern end and one at the northern end. There were therefore six beams left which formed the western wall without any part of them serving as extensions of the long walls. This is what was meant by verse 22 ולירכתי המשכן תעשה ששה קרשים, “and for the end of the Tabernacle you are to construct 6 beams. This verse reveals a mystical dimension. Seeing that the Shechinah which is situated in the west is composed of 6 extremities, the west is referred to as ים in order to allude to this fact. The west is known as ים, “ocean” because the ocean is a collection point for all the waters just as the Shechinah is a collection point for all the directions of the globe from the farthest extremities.
The order of the four geographical directions of the world in the celestial entourage, מרכבה, are: the three patriarchs of the world (Avraham Yitzchak and Yaakov), and David. South ranks first as Avraham was the first of the patriarchs, and it is written of him that Avraham journeyed southwards to the land of the south (Genesis 20,1). This is followed by north, as Yitzchak made a supreme effort at the time he was bound on the altar. This is followed by east seeing it is written of Yaakov that the sun shone for him (Genesis 32,32), and his son Joseph has also been compared to the sun (Genesis 37,9). Our sages (Bereshit Rabbah 84,11) have said quoting Yaakov: “who told this one (Joseph) that my name is “sun?” West is the סוף, the end; it is the harp on which David played which used to play all by itself on occasion (Berachot 3). This direction was called ים, i.e. the sea known as ים האחרון, the westernmost sea. In order to allude to these four great men the directions of the earth have been identified with these people through their names.

The planks were cut out at the bottom. . . Explanation: The bottom of the plank was cut out in a way that left intact one-quarter of the [width of the] plank on one side, and the same on the other side. And the cut-out part in the middle was one-half of the [width of the] plank. [Then, the one-quarters on the sides were partially cut out, to form the pegs]. For otherwise, [if Rashi meant to cut away one-quarter of the plank on each side, and also to cut away one-half in the middle,] nothing would remain from the width of the plank. And what then does Rashi mean by, “Thereby forming two pegs that were similar to two legs”?