Tamid 26A

במסיבה ההולכת לו תחת הבירה. ונרות דולקין מכאן ומכאן. עד שהוא מגיע לבית הטבילה. ומדורה היתה שם. ובית הכסא של כבוד. זה היה כבודו: מצאו נעול ⁠– יודע שיש שם אדם. פתוח ⁠– בידוע שאין שם אדם.

through the circuitous passage that extended beneath the Temple, as he could not pass through the Temple courtyard, due to his impurity. And there were lamps burning on this side and on that side of the passage. He would walk through the passage until he reached the Chamber of Immersion. And there was a fire burning there to warm the priests after they had immersed, and also a latrine of honor, so that the priests could urinate before immersion. This was the manifestation of its honor: If one found the door closed, he would know that there was a person there, and he would wait for him to exit before entering. If one found the door open, it was known that there was no person there, and he could enter. In this manner, the one using it was afforded privacy.

ירד, וטבל, עלה ונסתפג, ונתחמם כנגד המדורה. בא, וישב לו אצל אחיו הכהנים, עד שהיו שערים נפתחים, יוצא והולך לו.

After the priest descended and immersed in the mikveh, he ascended and dried himself with a towel, and warmed himself opposite the fire. He then came back to the Chamber of the Hearth and sat with his brothers the priests until dawn, when the gates of the Temple courtyard would be opened. He would then leave the Temple and go on his way. Since the purification process of one who immerses is not complete until sunset, by rabbinic law he could not remain in the Temple during the daytime.

מי שהוא רוצה לתרום את המזבח, משכים וטובל עד שלא יבא הממונה. וכי באיזה שעה בא הממונה? לא כל העתים שוות, פעמים שהוא בא מקרות הגבר, או סמוך לו מלפניו או מאחריו.

The Mishnah describes the commencement of the daily service in the Temple: Among the members of the priestly family who are to serve in the Temple that day, whoever wants to remove the ashes from the altar rises early and immerses himself in a mikveh, as required of anyone who enters the Temple courtyard. He must immerse before the appointed priest arrives, as the appointed priest oversees the lottery that determines which priests perform the various rites of the Temple service, and the first of those lotteries determines who will be charged with the removal of the ashes. And at what time does the appointed priest arrive? The times of his arrival are not all the same. There are times that he comes at the call of the rooster [hagever], or he might come at an adjacent time, either before the call of the rooster or after it.