Midrash for Sukkah 110:4
בשביעי כולן שוין בשמיני חזרו לפייס כברגלים אמרו מי שהקריב פרים היום לא יקריב למחר אלא חוזרין חלילה:
7) On the seventh day all were equal. 8) On the eighth day they again cast lots as on the other festivals. 9) They said: the [watch] that offered bulls on one day should not offer them on the next, but that they should take their turns in rotation.
Sifrei Devarim
Whence is it derived that all the priestly watches share equally in the (devoted portions of the) offerings of the festival? From (6) "then he shall come in all the desire of his soul to the place that the L-rd shall choose." I might think that the same holds true for all the days of the year; it is, therefore, written (6) "from one of your gates" — when all of Israel are assembled within one gate, i.e., during the three festivals.
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