Sons of Zadok
The Sons of Zadok ( bǝnê Ṣādōq) are a family of priests (kohanim), descended from Zadok, described in the prophecies of Ezekiel. Zadok himself was the first high priest in Solomon's Temple (10th century BCE). His descendants were high priests in that temple until its destruction in 587 BCE. Ezekiel's prophecy came several decades after that destruction, and describes the Zadokite family's loyalty to God while the rest of the nation rebelled against God. The sons of Zadok are mentioned four times in the Hebrew Bible, as part of the Third Temple prophecy in the final chapters of the Book of Ezekiel, and are a theme in Jewish and Christian interpretation of these chapters. Hebrew Bible 
 describes the "rebellion" of the Israelite people and of the Levites. The sins involved in this rebellion include idol worship and the offering of sacrifices by uncircumcised foreigners. As punishment, the "Levites" (including non-Zadokite priests, who are not called priests because they have lost their priestly role) will be demoted from the sacrificial service and will only perform common tasks. In contrast (the prophecy continues), the "Levite priests, sons of Zadok" remained loyal to God when the remainder of the people strayed, and therefore they will be entitled to perform the future sacrificial service. The passage then continues with a series of laws the sons of Zadok must keep. Rabbinical commentary

Choice of Zadok
According to the Bible, Aaron received a perpetual priestly covenant by which his descendants, and only his descendants, would be priests. According to some commentaries, the priesthood was further restricted to descendants of Aaron's son Eleazar after Eleazar inherited Aaron's priestly robes (), and further restricted to descendants of Eleazar's son Pinchas after Pinchas performed his act of zealotry. Nevertheless, later on the high priesthood was held by Eli, a descendant of Itamar (Eleazar's brother). Torah commentators attribute this to Pinchas' later sins (not instructing the masses in the leadup to the Battle of Gibeah, and not relieving Jephthah of his vow). But upon the sin of Eli's sons, Hophni and Phinehas, a "man of God" prophesied the extinction of their priesthood: 

This prophecy was fulfilled when Zadok, who was descended from Eleazar and Pinchas, was appointed as high priest. Rashi comments that since Zadok was the first high priest to serve in Solomon's Temple (as opposed to the mobile tabernacle), and also busied himself with establishing the twenty-four priestly divisions, he merited that the preferred lineage of Eleazar be called by his name, "the sons of Zadok" (as opposed to being titled the sons of Eleazar), and the entire concept of the twenty-four divisions be attributed to him. Choice of Zadok's descendants
Ezekiel records the general rebellion of the children of Israel against God. Rabbinic commentators understood this general rebellion as referring to that of Jeroboam and the Ten Tribes against the Kingdom of David and the priesthood of Zadok. According to Malbim, the period of idol worship initiated from the rebellion of Jeroboam up until the destruction of the First Temple. As recognition for not participating in idol worship and for actively and publicly sanctifying God's name, the sons of Zadok were granted numerous benefits in the Third Temple. Several commentators liken this to the case of a king, who after suppressing a rebellion, rewards those individuals who stood firm and did not join the rebellion. Asher ben Jehiel likens the public actions of the sons of Zadok to those of the Tribe of Levi at the time of the sin of the Golden Calf. In describing the uniqueness of the sons of Zadok, Rabbinic commentators liken their ability to reject Idol worship to that of a person with immunity against a plague, thus allowing them to function normally while others succumb to its undesirable results. Koheleth Rabbah relates how Zadok and offspring were righteous in their personal actions and Temple service, to the point that were Aaron and his sons present at the era of Zadok and sons, Zadok and sons would supersede them in quality. Priestly role
The book of Ezekiel details that the family line of priests, sons of Zadok, will execute the primary services in the Third Temple, that is the services of the altar of the burnt-offering. Similarly, the High Priest must be a descendant of Zadok. Malbim comments that non-Zadokite priests, who submitted to idol worship, are not eligible to Temple service, but they will be allowed to consume terumah and kodesh (sacrificial meat). Ezekiel describes the sons of Zadok as conducting the main sacrificial services in the Third Temple, particularly animal sacrifices ("bring to me fat and blood") and organizing the showbread ("come close to my table"). Jonathan Eybeschutz ascribes a symbolic meaning to this terminology. "Fat and blood" symbolizes the union of spirituality and physicality, as opposed to the word mincha (offering) which usually connotes a vegetable offering. Additionally, the showbread table is placed to the North side of the Temple, symbolizes monetary control (according to kaballah, north is synonymous with monetary issue), suggesting that the sons of Zadok will not fall temptation to bribery or similar corruption. As semi-high priests 
Rabbinic commentators on Ezekiel 44, such as Jonathan Eybeschutz, Isaac Abrabanel, Malbim, argue that after the coming of the Messiah, all sons of Zadok will have the status of "semi" high priests. This is alongside the choice of one of the sons of Zadok to be the full high priest. One source describes the future high priest from the sons of Zadok as being equal in certain ways to the future Jewish Messiah King. One commonality between the High Priest and the Sons of Zadok appears in the listing of family members for whom they may or may not become defiled. In both cases, the father is listed before the mother, in contrast to the standard priest, where the mother is listed before the father. Another commonality is the animal used for the inauguration by the sons of Zadok of the altar of burnt offering; this animal should be a bull, the same animal typically reserved as a sacrifice of the high priest. Garments of linen 

The sons of Zadok are instructed to don priestly clothing exclusively made of linen when performing Temple service, and to refrain entirely from using wool, commonly used in the standard priestly sash. Commentators write that wearing exclusively linen clothing is considered haughty and showy, therefore the sons of Zadok are permitted to wear clothes of wool when going out to mingle with the nation. An additional explanation to refraining from wool during service in the inner court is the nature of sheep to graze in any field they find – even one that the owner does not specifically give permission to (i.e. theft), whereas linen – as a crop – grows where the sustenance-source of the crop is taken by and with the will of the field owner. Some kabbalists state that the spiritual source of the Sons of Zadok is that of the sitra of Cain (In the Kabbalah Cain's soul belongs to the Sitra Ahara, the demonic side), where Cain's spiritual source will be elevated to goodness in the messianic era, and therefore are instructed to don linen for the temple service, as it was the fruit of the linen crop that Cain chose to sacrifice to God. Marriage prohibitions 

Ezekiel 44 prohibits "priests, Levites, sons of Zadok" from certain marriages:

The priestly prohibition on marrying divorcees is already known from . However, the inclusion of forbidding a widow, which was usually permitted to a common priest, is a subject of Rabbinic debate. The Talmud Bavli reads that the earlier part of Ezekiel 44 relates to the sons of Zadok, whereas 44:22 relates to priests who are not of Zadokite descent, meaning that the Zadokites, like the high priest, were forbidden from marrying a widow. This explanation is echoed by the Malbim, Jonathan Eibshitz, and other commentators who see the future status of the sons of Zadok in a Third Temple as quasi-high priests. Jonathan Eybeschutz explains that the widow of a priest is instructed by Ezekiel to marry another priest so as not be demoted from eating terumah, but she is nonetheless forbidden from marrying the sons of Zadok. Similarly, others explain that since the sons of Zadok are ordered by Ezekiel to be active in the Torah instruction of the Kohanim, the need to have a positive public image is crucial and marrying a widow may cause gossip and rumor that the Zadokite priest had transgressed forbidden relationships in Judaism. Similarly, there is the concern that the widow of a non-priest was initially a divorcee, and over time this fact was forgotten, whereas the widow of a priest is likely not a divorcee since all priests are forbidden from marrying divorcees. Jonathan Eybeschutz argues is the marital life with a widow is not one of full tranquility. As well, the wording of Ezekiel directs the Zadokite priest to marry a virgin, as he is to maintain a disposition of peace. Malbim favors the initial marriage of the sons of Zadok with the daughter of a priest. Others understand the ending part of the verse to concern the Sons of Zadok as well (i.e. a Son of Zadok is permitted to marry the widow of another priest). The Chasam Sofer reasons that only the widow of the priest is permitted to the Sons of Zadok, since the purity (marital integrity) level of the former wife of a priest is of greater quality than that of the standard daughter of Israel. Along this style of reasoning, others explain that the turmoil of the Jewish diaspora is cause for loss of marital integrity amongst the greater Jewish population whereas the Kohanim are more apt at maintaining an above-average standard of integrity for their spouses -thus the widow of a priest is permitted to the sons of Zadok. Torah instruction 
The sons of Zadok are directed to provide Torah instruction to the people. This instruction appears to be redundant to the standard portrayal of the priest as instructor (see The Torah instruction of the Kohanim). Chaim Yosef David Azulai, based on the writings of Samson ben Pesah Ostropoli, explains that the sons of Zadok are required to commit to judging monetary disputes, and are divinely blessed with an inherent ability to conquer the negative attribute of forgetfulness and to judge truthfully. Guarding Shabbat
Similarly, the sons of Zadok are told to guard Shabbat. This too appears to be redundant. According to Malbim, since priests are permitted to do certain activities prohibited on Shabbat due to sacrificial activity that override Shabbat in the Temple, they must be reminded not to do the same outside the Temple. Similarly, due to their requirement to engage in judicial activity, they may transgress Shabbat by writing legal notes. Likewise, there is the need to ascertain the sons of Zadok will not issue a death sentence on the Shabbat. Kabbalists declare that in the Messianic era the concept of nightfall and darkness will cease. As there will be no visual indication of the beginning of Shabbat, the sons of Zadok will be responsible for indicating this time to the nation of Israel. Zadok HaKohen writes that the observance of Shabbat by the priests, who are otherwise sustained by the twenty-four kohanic gifts rather than working, causes a surplus of kedusha to the entire nation of Israel and protects them from submitting to evil impulses. Apportioned chambers 

Due to the sons of Zadok performing the sacrificial services of the Third Temple, a specified chamber is apportioned to them as per the architectural detail laid out by Ezekiel. The verse describes one unique aspect of this chamber (compared to the other chambers) in the aspect that its entry-point faces north (as opposed to the other chambers opening towards south). Torah commentators describe that since the Zadokite priests are given the duties of the altar of burnt offering, therefore their chamber is situated at the South of the ramp leading up to the Mizbeach, with the entry and exit to their chamber facing North, thereby allowing them direct access to this ramp. The text in Ezekiel does not record the size of this chamber, nor describe if it is split into multiple rooms or is one large room. Estates in Jerusalem 
As part of Ezekiel's  vision of the division of the Land of Israel to the Twelve tribes of Israel and to the Messiah, the apportioning of a swath of land to the Sons of Zadok around the Temple Mount is mentioned. The measurement of this area is specified as 4,750 kanns (the kann measurement of Ezekiel is described as six amahs, with each amah consisting of six tefachs) beginning from the southern end of the Temple Mount heading South and from the opposite edge of the Temple Mount leading North, 12,250 kanns leading West and likewise to the East. This portion of the sons of Zadok is included in the 25,000 by 25,000 kanns that are to be given the greater Tribe of Levi with the greater tribe of Levi including Kohanim as well. Identifying Kohens of Zadokite lineage 
Rav Hai Gaon, in a letter sent to the Priests of Djerba (see also Beit Knesset Kohanim HaDintreisa), describes multiple personality aspects to be used in identifying genuine Kohanim. He describes the character traits of the Kohanim sons of Zadok as such:

Known priests of Zadokite lineage 
Priests in the Hebrew Bible of Zadokite lineage include Ezra and his relative Joshua the High Priest. Rabbis of Zadokite lineage include Eleazar ben Azariah (noted as being of tenth generation lineage to Ezra) and his descendants Rabbi Ezra and Rabbi Avtulas. Rabbi Rifael Ziskind Katz of Hamburg was likewise known to be a descendant of the biblical Ezra, his patrilineal descendants include HaRav HaNazir, She'ar Yashuv Cohen, and Yoel Kahan. Rabbinic literature indicates that there were numerous priestly families of Zadokite lineage – amongst them David HaKohain Bar Isha, who upon the Spanish expulsion in 1492, emigrated to the town of Debdou in Morocco – a town purported to have consisted of a large population of Jewish priests. Second Temple sects

Qumran
Various documents of the texts found at Qumran mention the teachers of the community as "kohanim Sons of Zadok", leading some scholars to assume that the community at Qumran included priests who refused to participate in the Hellenization of the priesthood then taking place in Jerusalem. Sadducees 

Abraham Geiger (1857), the founder of Reform Judaism, was of the opinion that the Sadducee (Tzadoki in Mishnaic pronunciation) sect of Judaism drew their name from Zadok the high priest in The First Temple, and that the leaders of the Sadducees were in fact the "Sons of Zadok". However Avot of Rabbi Natan (5:2) states that the Sadducees began at the same time as the Boethusians, and their founder was a later Zadok who, like Boethus, was a student of Antigonus of Sokho during the second century BCE. In Christianity
The idea of a literal fulfillment of Ezekiel's Third Temple in Jerusalem is an idea shared between some schools of Judaism and some millennial or adventist Protestants. These beliefs may include the reinstatement of animal sacrifices, and the reestablishment of a Zadokite priesthood: 

This verse also compares Revelation 1:4–5, 5:9–10 stating that all who are saved by His blood, also are made priest unto God the Father. It speaks of a present priesthood existing as well as into the future for all Christians. In literature
Shmuel HaNagid alluded to the loyalty of the sons of Zadok in his poem:

See also 

 Essenes
 Related Bible parts: Ezekiel 43, Ezekiel 44
 The Mitzvah of sanctifying the Kohen

External links 
 DNA family project for kohanim sons of Zadok at Family Tree DNA

References 

Priesthood (Judaism)
9th-century BC clergy
Dead Sea Scrolls
Essene texts
Book of Ezekiel
Jewish families