Yom Kippur Musaf-offering
Requires Beit HaMikdash
BaMidbar 29:7-8 On the tenth day of this seventh month there shall be a sacred holiday to you, when you shall fast and not do any work. You shall bring a olah-offering for a pleasing aroma to Hashem, one young bull, one ram, and seven yearling lambs. They shall [all] be without blemish.
We are commanded to offer a Musaf-offering on the 10th day of Tishri. The Musaf-offering here referred to was not considered part of the special service of the Day. Hence when presenting it the Kohen Gadol wore the customary eight golden robes, in which he was wore to perform the service in the Sanctuary throughout the whole year; but when presenting the special offerings for Yom Kippur, the Kohen Gadol was attired in the four linen robes specially prepared for that service.