The Torah dictates that the descendants of Aaron (the Kohanim) be separated from within the tribe of Levi and be prepared to serve in the Holy Temple (or Tabernacle).1

Aaron had two surviving sons, Elazar and Itamar. At first, Moses divided the Kohanim into eight groups, known as “watches” (mishmarot): four from the progeny of Elazar and four from Itamar. Due to the population growth and increasing need, the prophet Samuel further divided the Kohanim into 16 groups, and shortly thereafter King David (together with Samuel) further divided them into 24 watches.2

Since the family of Elazar was much larger than Itamar, 16 of the 24 watches were descendants of Elazar, while only eight were from Itamar.3

The Book of Chronicles describes how lots were cast to determine the order in which the different watches served in the Temple. It also lists the names of each family, together with the number of their watch in the 24-watch rotation.4

Each watch would go up to Jerusalem and serve in the Temple for one week, from Shabbat to Shabbat. The watches themselves were subdivided into seven groups, called batei av (“paternal house”), which each served on a different day of the week.5 When things would get too busy for one beit av, Kohanim from the same mishmar would pitch in.

The Mishmar on Shabbat and Holidays

The mishmarot would change on Shabbat. The outgoing mishmar would offer the morning and musaf (“additional”) sacrifices, while the incoming mishmar would offer the evening sacrifice and place the new showbread on the Table.6 The bread was split between the incoming and outgoing mishmar.7

During the pilgrimage festivals, all the watches should share equal status. Therefore, any Kohen who came during the pilgrimage festivals and desired to serve in the Temple was allowed to do so and would receive a portion of the offerings.8 Additionally, if a Kohen was bringing his own sacrifice, he was permitted to do the service himself.9

Only Four Families Left—New Division

We read in the book of Ezra that after the Babylonian exile, when the Jews came back to Israel to build the Second Holy Temple, only four families, totaling 4,289 Kohanim, came up with them. The rest either didn’t survive the destruction of the First Temple or remained in exile.

The prophets Haggai, Zechariah and Malachi then divided these four families into 24 watches.10

One of the kinot11 (elegies traditionally recited on the 9th of Av commemorating the destruction of the Temple) lists the names of the 24 cities or settlements where the different mishmarot resided, which were destroyed by the Romans. This elegy is the only surviving source for many of the cities where the Kohanim lived.

According to the Geonim, the watches took upon themselves the same names of the watches during the First Temple, as listed in the Book of Chronicles.12 The mishmarot during the Second Temple period were also known by the names of the cities they lived in, as listed in the above-mentioned elegy mourning their loss.

Twenty-Four Watches of Israelites

A sacrifice could only be offered with the person standing in attendance. During the communal offerings, the prophets ordained that there be a selective group of pious Jews in attendance, serving as the agents of the entire Jewish people. They were called "the men of the maamad" and were divided into 24 groups, mirroring the watches of the priests and Levites.

Each week, the members of the ma'amad would gather together. Those living in Jerusalem or close to it would enter the Temple with the priestly and Levitical watch of that week. Those hailing from distant places would gather in the synagogues of their locale and would fast, pray and hold special Torah readings.13

Traces of the Mishmarot in the Cairo Genizah

An ancient liturgical poem (piyut) found in the Cairo genizah, dated 1034 CE, customarily recited each Shabbat, mentions the name of the watch for that Shabbat, the number of years it was since the destruction of the Holy Temple, and a prayer that the Temple be rebuilt.

Additionally, there was an ancient custom to learn one chapter of the 24 chapters of Tractate Shabbat each Shabbat. Each chapter corresponds to another mishmar. An ancient copy of Mishnayot found in the Cairo genizah lists the name of a watch before each chapter.

Kohanim Drinking Wine

Priests were not allowed to serve or even enter the Temple if they were drunk. As such, if a Kohen nowadays would know which watch he was in, he would not be allowed to drink during the time that his watch would traditionally serve in the Temple.14

The Rebbe would often point to this halachah as evidence that the final Redemption and subsequent building of the Temple could take place in such a short time that a person could not even sober up before his time to serve would arrive.15

May we merit the final Redemption and building of the Temple speedily in our days!