Reform Judaism has done away with a number of ritual observances that conflict with our contemporary cultural and aesthetic sensibilities. And it is difficult to imagine any ceremony that stands more at odds with the views and habits of modern civilization than berit milah, ritual circumcision. Critics of the procedure, including a not-insignificant number of Jews, condemn it as a gruesome and dangerous procedure, some calling it “genital mutilation.” Many would add that a ritual from which females are naturally excluded calls into question our Reform Jewish commitment to gender equality.

Yet this practice survives. Indeed, berit milah is enjoying somewhat of a renaissance in our Movement.

Historians tell us that Reform Jews never abandoned circumcision—it has been a red line Reform Judaism has never crossed. For many years it was a purely surgical procedure performed in the hospital without accompanying ritual. In recent decades, however, our people have transformed “circumcision” into berit milah; that is, we have rediscovered its significance as a ritual act. Accordingly, we perform circumcision in the setting of its traditional liturgy, which includes the recitation of blessings (berakhot) that praise God “who has sanctified us through mitzvot and commanded us” to bring our sons “into the covenant of Abraham our father,” and have added the Sephardic custom of reciting shehechiyanu, thanking God for making it possible for us to reach this joyous event. And in 1984 our Movement established the Berit Mila Program of Reform Judaism, which trains and certifies qualified medical practitioners, men and women, as mohalim and mohalot.

The question remains, however: why do we Reform Jews, who do not hesitate to remove outdated prayers from our siddur (prayer book) and to excise archaic ceremonies from our practice, insist upon maintaining an ancient tribal rite taught to us in Genesis? (“God said to Abraham: ‘As for you, you shall keep my covenant [berit], you and your offspring to come, throughout the ages. Such is the covenant which you shall keep, between Me and you and your offspring to follow: every male among you shall be circumcised…,’” Genesis 17:9–10.) Why does Gates of Mitzvah, the Central Conference of American Rabbis’ preeminent “guide to the Jewish life cycles,” assert: “It is…a mitzvah to bring a male child into the covenant through the rite of circumcision—berit milah”? And why did the CCAR Responsa Committee state in 1982 that circumcision remains for us an essential sign of the covenant: “We have affirmed it since the days of Abraham, our Father, and continue to affirm it”?

I think that the answer to these questions lies largely in the words “ancient tribal rite.” For that’s what berit milah is. That’s why we do it, and, really, it’s the only reason we do it.

Circumcision is a tribal rite in the same way that every Jewish ritual observance is a “tribal rite”: a means by which the members of our “tribe” express their identity as a people, as a community covenanted with God, through the performance of a “rite” meaningful only within the context of that covenant. Putting it another way, if we seek to explain why we light Shabbat candles, or fast on Yom Kippur, or hold a Passover seder, it would be enough to say simply that “we do these things because we are Jews, because only Jews do them, and because we rehearse our uniquely Jewish identity by means of these uniquely Jewish acts.” Every tribe in the world behaves in this way, proclaiming its sense of community through the performance of rituals that allow the tribe to tell its story and to recount its sense of self. And make no mistake: we Jews are a “tribe,” a social grouping that has defined its existence and historical destiny as that of a family, an ethnos, a community that reproduces itself by giving birth to Jewish children. (The Jew-by-choice is no exception to this rule. According to our tradition, one who has converted to Judaism gives birth to or begets Jewish children, just as if she or he were a Jew by birth. One who chooses Judaism, in other words, has chosen to become a member of the tribe.) To say that we are a “tribe” is simply another way of saying that we are the people of Israel, a community that asserts its ongoing historical existence. This may be what the author of the Sefer Hachinukh, a late 13th-century Spanish presentation of the 613 mitzvot, had in mind when he offered this rationale for berit milah: “The Holy One desired to distinguish His people by means of a sign fixed upon their bodies, to set them apart in a physical sense from the other nations, just as they are distinct from those nations in a spiritual sense.” Translation: circumcision serves as an indelible physical mark of Jewish peoplehood. Tribal rite.

Of course, we don’t customarily explain our ritual observances as “tribal rites.” This is partly because the word “tribal” sounds so, well, tribal, jarring to our modern, sophisticated ears. It’s also because we Jews have a long history of seeking ta`amei hamitzvot, “explanations for the mitzvot” that reflect the higher intellectual and cultural temper of the present age rather than the original (“tribal”) background of those practices.

Berit milah is our classic ceremonial acknowledgment that we, descendants of Abraham, consider ourselves a community set apart from all others and set aside in covenant with God. That is the story we have always told, and continue to tell, about ourselves. To assert our sense of particular Jewish identity as Jews is therefore in and of itself a mitzvah of the first rank. And of all the ritual practices by which we have historically made that declaration, none is more physical, more visceral, or more tangible than berit milah.

In an era when the forces of cultural assimilation pose such a daunting challenge to our continued existence as a distinct people, this admittedly ancient tribal custom bears a message that we do well to hear.

Rabbi Mark Washofsky is professor of Rabbinics at HUC-JIR in Cincinnati, Ohio.