While working in the Beit HaMikdash, the Kohanim had to wear special garments, or their work would not count. The purpose of the garments was to separate the Kohanim from the other members of Bnei Yisrael while they were doing their priestly work. People had to realize that Aharon and his sons were on a higher spiritual level, and that was the reason they were the only people doing the work. The garments were a constant reminder to any onlookers and to the Kohanim as well that the way people approach a task influences others’ performance of similar tasks. Additionally, the fact that the Kohanim could do the service in their special clothing suggests that if a Jew involves himself in serving Hashem, he should take care to dress appropriately and have respect and dignity toward Hashem.
All of the priestly vestments were made of the materials that were property of the nation. The vestments were so special that the Kohanim could not even have a bandage separating their skin from the material. This lack of separation transformed the Kohen into a single vessel fulfilling Hashem’s will. The fact that the people donated their clothes showed that the Kohanim were not their own separate entity; rather, they became representatives of Israel, carrying out the nation’s urge to raise itself onto a higher level of spirituality. May we be Zocheh to see the Kohanim in their priestly garments in the third Beit HaMikdash.