In the second perek of Massekhet Yoma we will learn how the different jobs in the Temple were divided up among the kohanim who were working in the Mikdash at a given time. As we learned earlier (14a), the Mishna in our perek teaches that during the week before Yom Kippur it is the Kohen Gadol who burns the ketoret, arranges the menorah, and sacrifices the korban tamid (“perpetual” daily offering) on the altar. The Mishna adds that throughout the year it is the prerogative of the Kohen Gadol to choose which korbanot he wants to sacrifice and be the first to choose his portion from the korbanot.
The Gemara on our daf quotes a baraita that describes how the Kohen Gadol would walk through the Temple and claim the right to sacrifice a given korban by saying, “I will sacrifice that Olah” or “I will sacrifice that Minha.” He chooses what portion he will receive by saying, “I will eat that Hatat” or “I will eat that Asham.” Similarly, he receives one of the two loaves that are brought on Shavu’ot and four or five of the loaves of shewbread that is distributed weekly from the shulhan. Rabbi Yehuda HaNasi’s position is that he always gets five, since he deserves half of the ten loaves that are distributed, based on the passage in Vayikra 24:9 “And it shall be for Aharon and his sons,” which he understands to mean that Aharon (the High Priest) shares equally with his sons (the other Kohanim).
The Rashash points out that there is support for the idea that the Kohen Gadol received five loaves of the lehem ha-panim from the story related in Sefer Shmuel (21:4) when David is running away from King Sha’ul, and arrives in Nov, the city of kohanim. Upon asking for food, Akhimelekh, who was apparently the Kohen Gadol at the time, tells David that he only has “holy bread.” David agrees to take the lehem ha-panim (after assuring Akhimelekh that his men are in a state of ritual purity), and he receives the five loaves that he requested.