Middos 1:1 - 1:2

בשלשה מקומות הכהנים שומרים – not because of fear of robbers and/or thieves, but that of the honor and splendor for the Temple, that it should not be without guards, and this guarding, its commandment is the entire night. And these three places that the Kohanim guard correspond to what is written in the Torah (Numbers 3:38): “Those who were to camp before the Tabernacle, in front – [before the Tent of Meeting, on the east – were Moses and Aaron and his sons,] attending to the duties of the sanctuary, as a duty on behalf of the Israelites,” as a hint to three watches in three places. For just as that in the Tabernacle, Aaron and his two sons were guarding in three places, even so in the Temple as well.

בית אבטינס ובית הניצוץ – two upper chambers were built on the side of the gates of the Temple courtyard, but the House of the Hearth was not upon it, but rather an arch , ARKVELT in the foreign tongue, which was made in the land, such was explained at the beginning of the Tractate Tamid (1:1).

והלוים בעשרים ואחד מקום – that in twenty-four places they would need to guard the Temple, as it is written in [First] Chronicles [26:17-18): “At the east – six Levites; at the north – four daily; at the south – four daily; at the vestibule – two by two; at the colonnade on the west – four at the causeway and two at the colonnade,” that makes here twenty-four divisions of duty/watches, three of them were Kohanim as we stated in the opening clause [of the Mishnah], and twenty-one of them were Levites. But even though that Scripture did not state anything other than Levites, Kohanim are also called Levites , as it is written (Ezekiel 44:15): “But the Levitical priests descended from Zadok [who maintained the service of My Sanctuary when the people of Israel went astray from Me – they shall approach Me to minister to Me.”

חמשה – guards at the five gates of the Temple Mount.

מתוכו – from inside to the walls of the Temple Mount.

על חמשה שערי עזרה – this Tanna/teacher holds that there are only five gates for the Temple courtyards But even according to the one who states further on (see Tractate Middot, Chapter 1, Mishnah and Tractate Tamid 27a), he admits that there wasn’t a division of duty/guard other than on five [gates of the Temple courtyard – that the House of the Flame and the House of the Hearlth were watched by Kohanim or that the gates that were in the middle of the north and the south didn’t require special guarding, as they were guarded by those at the first and third gates].

על ארבע פנותיה מבחוץ – because there is no sitting in the Temple courtyard other than for only the kings of the House of David, and it was not possible for a guard to watch while standing all the night, therefore, the guards were in the corners of the Temple courtyard, and similarly, the guards in the gates of the Temple courtyard would guard from outside, in order that they would be permitted while sitting, and the Scriptural verse (First Chronicles 26:18) esd used as a support (i.e., they leaned their enactment against a Biblical text) – as it is written: “two at the colonnade,” towards the outside, meaning to say, outside the wall of the Temple courtyard.

איש הר הבית – appointed over all of the guards. [The story is told in Tractate Yoma 16a that Rabbi Eliezer ben Yaakov, the first of two Tannaim of such a name, who was the friend of Rabbi Eliezer the Great/ben Hyrcanus – was the Tanna who taught Tractate Middot.