Regarding a daughter of such persons, opinion in the Mishnah is divided as to whether or not it was necessary that one of the parents should be of Jewish descent. The decision of later authorities was that, in case both of the woman's parents were proselytes or freed persons, a priest should not marry her, but if he had done so, then the marriage should be considered legitimate.

A Kohen not complying with these requirements is not allowed to give the priestly blessing.

Talmudic law prescribes that the honor of being first called upon for the reading of the Torah should belong to the priest.

According to the Talmud, the regulations demanding an unimpeachable pedigree continued to be binding, even after the Temple had been destroyed. The reason is that eventually the Jewish Messiah will arrive, gather the Jews back to the land of Israel, rebuild the Temple, and resume the priestly service; at such a time Kohanim of unimpeachable status will be required for such service.

Rules protecting against ritual defilement

Even in death, many Kohanim choose to have this symbol, the position of their fingers and hands during the priestly blessing, placed as a crest or symbol on their gravestones, to indicate their status.The Kohanim formed a holy order. For the purpose of protecting them against all ritual profanation and defilement they were to follow many rules.

• Kohanim were forbidden to come in contact with dead bodies, except in the case of their nearest kin, nor were they permitted to perform the customary mourning rites. A Kohen is forbidden to enter any house or enclosure, or approach any spot, where a dead body, or part of a dead body, may be found. (Lev. x. 6, xxi. 1–5; Ezek. xliv. 20, 25).
• A Kohen is forbidden to touch any one or anything that is ritually unclean through contact with the dead.
• They were not allowed to marry harlots, nor dishonored or divorced women (Lev. xxi. 7).T
• They were required to abstain from wine and all strong drink while performing sacerdotal duties (Lev. x. 9; Ezek. xliv. 21).
• Any priest having incurred Levitical defilement was excluded, under penalty of death, from priestly service and from partaking of holy food during the time of his uncleanness (Lev. xxii. 2–7, 9; Ezek. xliv. 26 et seq.).
• If afflicted with any bodily blemish the priest was held permanently unfit for service; however, they were still permitted to eat of the holy food (Lev. xxi. 17–23). The Talmud specifies what constitutes a bodily defect sufficient to render a Kohen unfit for priestly service.

Exceptions to rules for contact with the dead

In contradistinction to Lev. 21:2–4, the Talmud includes a Kohen's wife and children among the persons of immediate relationship. Thus, it specifies that a Kohen must take care of and bury his dead wife and children, even though a strict reading of the Torah would mean that this renders the Kohen ritually impure.

The Talmud prescribes that if any Kohen, even the Kohen Gadol (high priest), finds a corpse by the wayside, and there is no one else in the area who can be called upon to inter it, then the Kohen himself must perform the burial.

The Talmud orders the Kohen to defile himself in the case of the death of a nasi (rabbinic leader of a religious academy). The Talmud relates that when Judah haNasi died the priestly laws concerning defilement through contact with the dead were suspended for the day of his death.

Division into work groups

Not all Kohanim (priests) worked at the same time; they were divided into twenty-four groups. This is mentioned in Chronicles; this practice continued down to the destruction of the Second Temple, as statements to this effect by Josephus ("Ant." vii. 14, § 7; "Vita", § 1) and the Talmudic sources show.

These "divisions" of priests took turns in weekly service. Those who served changed every Shabbat (Sabbath), but on the Biblical festivals all twenty-four were present in the Temple.

These twenty-four "divisions" were subdivided into from five to nine smaller groups. Each of these smaller groups was assigned to service in turn. The main "divisions" were called mishmarot, the "subdivisions" batte abot (terms which in Chronicles are used interchangeably). There was a chief at the head of each main "division", and also one at the head of each "subdivision".

Post-Temple theology and practice

After the destruction of the Second Temple in Jerusalem the formal role of priests in sacrificial services came to an end, since in the absence of a temple in Jerusalem, sacrifices are not brought.

Women and the priesthood

A Bat Kohen is the daughter of a Kohen. The Talmud states that she loses her status as a Kohenet (i.e. "female Kohen") when she marries a non-Kohen. Some rulings in traditional Jewish law allow for the ruling that a Bat Kohen may perform the ritual of pidyon ha-ben, the ceremonial redemption of a first-born son. In practice Orthodox Judaism views this as forbidden. A Bat Kohen may not perform the ritual of Nesiat Kapayim, the priestly blessing sung aloud from the pulpit towards the congregation.


Marriages involving Kohanim

Historic and present-day Orthodox Judaism view
Such marriages are regulated by a number of special restrictions in addition to the general laws covering all Israelites. The Torah prohibits a Kohen from marrying women of certain specified categories: A divorcee, a "defiled" woman, or a "harlot". It ordains that any Kohen who makes such a marriage loses his priestly status [Lev. 21:6–7]. The Talmudic understanding of the word "harlot" also encompasses the meaning "proselyte" (or "convert"). According to the Talmud the act of marriage, although prohibited, was effective if a Kohen married in disregard of the prohibitions. Any children born of the union are legitimate.

Since the destruction of the Temple in Jerusalem, there have been no more sacrificial services, but the sanctified status of the Kohanim remains in force.

Reform view

Reform Judaism sees ritual halakha as no longer having any legal status, and this allows such marriages. Orthodox Judaism accepts that these laws are still normative, and thus usually forbids such marriages.

Conservative Judaism view

Conservative Judaism holds that, in general, Jewish law is still binding, but that these particular restrictions are no longer applicable. Thus the movement teaches that a Kohen may marry a convert or divorcee. Their reasoning is that:

The Temple in Jerusalem is no longer extant; Kohanim are no longer needed to perform Temple services.

According to many codes of Jewish law, the priestly status of most Kohanim is doubtful, at best. Rabbi Isaac ben Sheshet (14th century) differentiates between authentic Kohanim of ancient times, and those who carry the title today. He rules that today's Kohanim, lacking documentary evidence of clear right to the priestly title, owes any privileges and obligations not simply to halakha (law) but rather to the force of minhag (custom). [Sefer Bar Sheshet, responsum 94, Lemberg, 1805].
Rabbi Solomon Luria (16th century) rules that because of the frequent persecutions and expulsions of Jews throughout history, Kohanim lost track of their genealogy. The Magen Avraham also rules this way, and Rabbi Jacob Emden ruled similarly.
The intermarriage crisis in American Judaism is an extreme situation, and the movement feels it must support the decision of two Jews to marry.
See also the entry on the Jewish view of marriage

Kohanim in contemporary times

Orthodox Jewish views

Since the end of the Temple in Jerusalem, the Kohen has little formal rule in Jewish life. The one area in which the Kohen still has a formal and public ceremonial comes in the area of the aliyah, the ritual reading of the Torah during prayer services. Three times each week a portion from the Torah is read aloud in front of the congregation, in the original Hebrew, and this reading is split into a number of portions. It is customary to reserve the first reading of the Torah for a Kohen, and the second reading of the Torah for a Levite. In the Orthodox Jewish community this custom has the effective status of law.

As Orthodox Judaism does not allow women to read publicly from the Torah during formal prayer services, daughters of Kohanim and Leviyim have no role in this area.

In regards to the ritual of pidyon ha-ben, the symbolic redemption of a newborn son, Orthodox rabbis note that there are some rabbinic sources which allow women to perform this ritual. In practice, however, the custom is to use only men.

In regards to the ritual of the Priestly Blessing, a Bat Kohen (daughter of a Kohen) is not permitted to participate in Nesiat Kapayim because as a continuation of a Temple ritual, the Priestly Benediction should be performed by those who were authentically eligible to do so in the Temple.

Conservative and Masorti Jewish views

The aliyah is the ritual reading of the Torah during prayer services. It is customary to reserve the first reading of the Torah for a Kohen, and the second reading of the Torah for a Levite. In the Conservative Jewish community this custom is generally followed, but it does not have the status of law. The Rabbinical Assembly's Committee on Jewish Law and Standards has ruled that a rabbi is not obligated to follow this custom. As such, in some Conservative and synagogues, this custom is not followed.

The following are the opinions of the Committee of Jewish Law and Standards (CJLS) of the Rabbinical Assembly, the international body of Conservative Jewish rabbis. Note that the Conservative movement teaches that where the law committee has validated more than one possible position, a congregation must follow the ruling of its rabbi, who as mara d'atra, local authority, has the sole responsibility in making such a p'sak, decision of Jewish law.

One position of the CJLS is that daughters of Kohanim and Leviyim can be accorded the same honor of reading publicly from the Torah that are normally accorded to Kohanim and Leviyim, whether they are single or married. Their status regarding being called to the Torah should not be determined by the lineage of their husbands, but by their own paternal lineage (Rabbi Joel Roth "The status of daughters of Kohanim and Leviyim for aliyot" 11/15/89). Another position is that women do not receive such aliyot. The law committee of the Masorti movement (Conservative Judaism in Israel) has also ruled that women do not receive such aliyot (Rabbi Robert Harris, 5748).
In regards to the ritual of pidyon ha-ben, the symbolic redemption of a newborn son, women may perform it on a newborn son. However, it is forbidden to perform this ceremony on a new-born daughter.

In regards to the ritual of the Priestly Blessing, the CJLS has approved two positions. One view holds that a Bat Kohen may participate in Nesiat Kapayim, another view holds that a Bat Kohen is not permitted to participate in Nesiat Kapayim because as a continuation of a Temple ritual, the Priestly Benediction should be performed by those who were authentically eligible to do so in the Temple. (Rabbis Stanley Bramnick and Judah Kagen, 1994; and a responsa by the Va'ad halakha of the Masorti movement, Rabbi Reuven Hammer, 5748)

Reform and Reconstructionist Jewish views

The majority of Reform Jews and Reconstructionist Jews consider all rules and ceremonies regarding the priesthood to be outdated. Many consider it to be anti-egalitarian, and thus discriminatory against Jews who are not Kohanim. Thus the above laws and customs are no longer observed in Reform or Reconstructionist Jewish communities. Many Reform and Reconstructionist Temples effectively forbid the practice of these laws and customs. Both Orthodox and Conservative Jews strenuously disagree with this latter view.

Who is a Priest?

King Melchizedek of Salem, identified by Rashi as being Shem the son of Noah by another name, is the first person in the Torah to be called a Kohen (Genesis 14:18).

When Esau sold the birthright of the first born to Jacob, Rashi explains that the Priesthood was sold along with it, because by right the priesthood belongs to the first born. Only when the firstborn (along with the rest of Israel) sinned at the Golden calf, the priesthood was given to the tribe of Levi, which had not been tainted by this incident.

Moses was supposed to receive the priesthood along with the leadership of the Jewish people, but when he argued with God that he should not be the leader, it was given to Aaron.

Aaron received the priesthood along with his children and any descendents that would be born subsequently. However, his grandson Pinchas (Phineas) had already been born, and did not receive the priesthood until he killed the prince of the tribe of Simon and the princess of the Midianites (Numbers 31:11–12).

Thereafter, the priesthood has remained with the descendants of Aaron. However, when the Messiah comes, there is a tradition that it will revert back to the first born.


Recent genetic findings: The Kohen gene

Recently the tradition that Kohanim are actually descended from Aaron was supported by genetic testing (Skorecki et al., 1997). Since all direct male lineage shares a common Y chromosome, testing was done across sectors of the Jewish population to see if there was any commonality between their Y chromosomes. There was proven to be certain distinctions among the "Kohen" Y chromosomes, implying that the Kohanim do share some common ancestry. This information was used to support the claim of the Lemba (a sub-Saharan tribe) that they were in fact, a tribe of Jews. See also Y-chromosomal Aaron.

Cohen as a surname

Many Kohanim have a surname that reflects their status, such as Cohen itself, Conn or "Anglicised" variants like Conway. Cogan may be due to a confusion between the h and g sounds in parts of Eastern Europe, or a corruption of Kagan. Katz may be short for Kohen Tzedek (Righteous Kohen). However, by no means all Jews with such surnames are Kohanim. Also, some Cohens may be Irish (corruption of Cohan).

Trivia

The gesture that a Kohen gives when blessing a congregation was Leonard Nimoy's inspiration for the Vulcan salute.