Why does the Kohen Gadol don white garments during the Yom Kippur service? Does this symbolize a heightened spiritual quality or perhaps a lower status? Yom Kippur is seemingly a day of new beginnings. The Kohen, together with the rest of the mishkan, are restored to their status prior to donning the white garments so that he will be able to once again wear his priestly garments in sanctity and purity. 

Courtesy of the Virtual Beit Midrash, Yeshivat Har Etzion