Yoma, Mishnah 3. In the previous mishnah we described the confession of the Kohen Gadol over the scapegoat - the goat that was sent away. In this mishnah we will describe the process of sending it out.
Handing the goat over to the one who leads it:
"Mesaro lemi shemolicho" - the Kohen Gadol handed the goat over to the man who would take it out to Azazel, into the wilderness.
Who is fit to lead it:
"Hakol kesheirin leholicho" - by strict law any Jew is fit and suitable to lead the goat out, and there is no requirement that he be a kohen.
"Ela she'asu Kohanim Gedolim keva velo hayu manichin es Yisrael leholicho" - the Kohanim Gedolim made this a fixed practice, and would not allow anyone who was not a kohen to lead the goat out, even though by law this is not required.
The view of Rabbi Yosi:
Rabbi Yosi disagrees and brings proof from an incident: "Ma'aseh veholicho Arsela, veYisrael hayah" - a man named Arsela once led the goat out, and he was a Yisrael and not a kohen.
In summary: in this mishnah we learned the process of sending out the scapegoat - handing it over to the one who leads it into the wilderness, the basic fitness of any Jew to lead it, the fixed practice established by the Kohanim Gedolim not to allow a Yisrael to lead it, and the view of Rabbi Yosi, who brought the incident of Arsela, who led it out and was a Yisrael.