Middot, Chapter One, Mishnah One
Tractate Middot opens with the same exact line as did Tamida list of where the priests kept watch all night. However, the interest of the two tractates is a bit different. Middot is interested in the watch itself, whereas Tamid was more interested in locating the priests before their daily work began.
The beginning of Numbers 18 states that the priests and Levites are to stand guard at the Tabernacle, an idea that was later applied to the Temple as well. It seems that this guarding could serve two functions: practical and ceremonial. The Temple is akin to a palace and a palace needs guard both for protection and protocol (think about the guards in front of Buckingham Palace). The idea that there were a total of twenty-four places in the Temple where either priests or Levites would stand guard is mentioned also in I Chronicles 26:17-18.
1) In three places the priests keep watch in the Temple: in the chamber of Avtinas, in the chamber of the spark, and in the fire chamber.
2) And the Levites in twenty-one places:
a) Five at the five gates of the Temple Mount;
b) Four at its four corners on the inside;
c) Five at five of the gates of the courtyard;
d) Four at its four corners on the outside;
e) One at the offering chamber;
f) One at the chamber of the curtain,
g) And one behind the place of the kapporet.
Section one: There were three places in the Temple where the priests would keep watch at night:
The chamber of Avtinas, where they would prepare the incense.
The chamber of the spark, where they kept the fire to light the fires on the altars.
The fire chamber where they kept a large fire to keep the priests warm at night.
Section two: There were twenty-one places where the Levites kept watch:
A: The five gates to enter the Temple Mount.
B: The four inside corners of the walls surrounding the Temple Mount. Sort of like prison guards.
C: There were seven gates to the courtyard (see mishnah four) but the Levites guarded only five of them.
D: At the four corners inside the walls surrounding the Temple.
E: The offering chamber was in the burning place. We will learn more about this place in mishnah six.
F: Where the curtain was kept.
G: This refers to behind the Holy of Holies.