שמות, פרק ל״ט, פסוק ט׳

The High Priest wore a unique garment upon his chest, crafted with exact measurements and a specific physical structure. The Breastplate was fashioned as a perfect square, measuring a single span in both its length and its width. A span is a traditional unit of measurement, roughly equivalent to half a cubit, or just over twenty centimeters. It is determined by the distance between the tip of the thumb and the tip of the pinky finger when a hand is stretched wide open [ביאור שטיינזלץ].

Rather than being a simple flat piece of fabric, the garment was folded over to create a double layer. This folded design formed a functional pocket or pouch. According to tradition, this hollow space was specifically designed to hold sacred, holy names within it [ביאור שטיינזלץ]. Furthermore, the double-layered nature of the garment reflected more than just its physical construction. The craftsmen who formed it worked with a specific mindset, intentionally designing the Breastplate to serve two distinct purposes simultaneously [העמק דבר].