שמות, פרק כ״ו, פסוק כ״ב

The architecture of the Tabernacle is designed with a clear sense of direction, establishing a distinct front entrance and a solid back wall. Because the entrance is situated on the eastern side, acting as the face or head of the structure, the opposite end naturally serves as the back. The primary approach among commentators is that this rear section faces west [רש"י, ביאור יש"ר, ביאור שטיינזלץ, קאסוטו]. Interestingly, the language used to describe this western direction borrows the word for the sea. This reflects the geographical reality of the land of Canaan, where the sea lies to the west, showing how the local landscape directly shaped biblical terminology [קאסוטו].

To construct this rear wall and enclose the rectangular space [ביאור שטיינזלץ], six boards are used. These boards are identical in their dimensions to those forming the sides of the Tabernacle [קאסוטו]. Since each board measures an exact width of one and a half cubits, placing six of them side by side creates a central wall spanning nine cubits [רש"י, ביאור יש"ר, רשב"ם].

A width of nine cubits, however, leaves a gap of half a cubit at both the northwest and southwest edges. To resolve this, two specialized corner boards are added. These corner pieces perfectly fill the remaining gaps, bringing the total internal width of the Tabernacle to exactly ten cubits. At the same time, they cover the exposed thickness of the boards running along the northern and southern walls, ensuring that the exterior corners of the structure remain perfectly square and flush [רשב"ם]. Finally, to keep everything firmly in place, the bottoms of these boards were carved to form stabilizing pegs, with a notch measuring a quarter of a cubit cut into each side [ריב"א].