It is interesting to note that, while this pasuk mentions six garments, instructions were actually given for the fabrication of eight garments. The tzitz, headplate, and michnasayim, breeches, are not mentioned here. Why are these garments left out of this pasuk?
Horav Dovid Feinstein, Shlita, suggests that on the one hand these two garments represent the elementary foundation of human decency. On the other, the garments represent the spiritual apex of the Kohen Gadol’s spiritual ascendency. These two garments were an obvious requirement. The Kohen Gadol needed to wear breeches for the sake of modesty. The fact that breeches were a necessity is an indication of man’s imperfection. He must cover himself prior to serving Hashem. The tzitz was the last item the Kohen Gadol put on. It was the culmination of his attire when he wrapped the words ‘vk ase, Holy to Hashem, on his forehead. The breeches represent the Kohen Gadol’s confrontation with his inadequacy and his ascendancy over it. The breeches created the foundation for the other garments, which reflected his spiritual development.
The tzitz was the zenith of his attire, giving meaning to everything “in between,” crowning his endeavors with spiritual success. Although the Torah explains the technical features of these two garments, it is unnecessary to mention the mandate to wear them. Every person should know that success is achieved by having rudimentary decency and striving for a sublime spiritual goal. The foundation one makes for himself and the development of his goal are the two most important criteria for success. These two garments are an accepted given, while the “in between” represent the methods for attaining this spiritual peak.