שמות, פרק ל״ט, פסוק ד׳

The Ephod worn by the High Priest functioned much like an apron or a skirt, secured firmly in place by specially crafted shoulder straps [ביאור שטיינזלץ]. When constructing these straps and attaching them to the main garment, the artisans made a deliberate design choice that adapted the original instructions.

Instead of leaving the straps separate to be fastened with hooks only when the garment was put on, the chief artisan, Bezalel, opted to sew them on permanently. He understood that a fixed, permanent connection would create a better, more secure garment [העמק דבר].

This practical decision to permanently attach the straps altered their very nature. Originally, the design allowed for the straps to be completely interchangeable between the right and left sides. However, once they were permanently stitched into place on specific sides of the Ephod, they could no longer be swapped. They became distinct right and left pieces, fixed permanently to the garment [העמק דבר].