As it barrels out of the Holy of Holies in the ancient Temple, on the run from the rabbis, humankind’s evil impulse to worship idols presents itself in the form of a fiery lion cub. But, as the Talmud records (in tractate Yoma), the rabbis manage to capture it. Alarmed by how loudly the cub wails upon a single hair’s being plucked—the sound can be heard for a thousand miles around—they’re loath to kill it outright. Instead, they encase it in a soundproof lead box.

But the rabbis’ work is not yet done. After trapping the cub they trap its cousin, the evil inclination toward sexual promiscuity. By doing so, however, they inadvertently thwart reproduction itself, to the point where hens cease laying eggs. So they content themselves with blinding and releasing this second spirit while continuing to imprison the lust for idol worship.

Then, many centuries later, yoga comes to America.

I. Jews and Yoga

Yoga represents a $16-billion industry in the U.S., reaching an estimated 36.7 million people in 2016 alone. On the basis of much anecdotal evidence, one would be safe in saying that among these dozens of millions are many members of the American Jewish community and, also, that among the latter are substantial numbers of traditionalist or Orthodox Jews. Indeed, one hears of synagogue-sponsored yoga programs and yoga “quorums.” Even a right-wing Orthodox educational organization like Aish HaTorah has seen fit to re-post on its website an item titled “How Orthodox Jews Taught Me Yoga.”

“What Draws So Many Jewish People to Yoga?” asks an article in the Canadian Jewish News. It’s a reasonable question. Unfortunately, the writer, who provides no numbers, doesn’t get any closer to an answer than the vague formula that both Judaism and yoga “recognize the importance of setting aside the mundane in order to focus on something higher.” Nor did the Pew Research Center pose any questions about yoga in its 2013 survey of American Jews, or in its 2014 survey of the general religious landscape.

According to Alan Cooperman, Pew’s director of religion research, the organization did find in 2009 that 23 percent of respondents affiliated with a religion saw yoga as, beyond physical exercise, a spiritual practice. These yoga-adepts were likelier to be female, Hispanic, young, and better educated, as well as Democrats, liberals, independents, or moderates. Although such surveys do not ask about respondents’ specific affiliations, many if not most of those modifiers fit the profile of American Jews.

And that leads to another reasonable question: what does Judaism itself have to say about yoga—a practice whose roots and much of whose animating spirit lie in a decidedly non-monotheistic world religion? Curiously, the subject appears to be a rare blind spot in the copious written or published opinions issued by Orthodox rabbinic authorities on almost every question raised by inquiring Jews. The rabbis who do address yoga tend also to stipulate that most of their peers feel they don’t know enough about the practice to issue rulings or guidance concerning it. (As if to illustrate the point, one rabbi said in a sermon that he had to discount the views of a colleague who revealed his ignorance by speaking of practitioners engaged in “bowing to the yoga.”)

Admittedly, much yoga practice today is no truer to its religious Hindu origins than the message of the Kabbalah Center is to the thought of the great 16th-century kabbalist Isaac Luria. But yoga teachers indisputably employ a vocabulary, and inculcate physical positions, that derive from centuries-old religious worship. Similarly, although Western yoga is a kind of abstraction, largely (though not entirely) stripped of the devotional images of deities to whom adherents once directed their movements and intentions, it’s not purely exercise.

In Sanskrit, the term yoga itself means “union,” as in the conjoining of worshipper and gods, and idol worship—of which this particular “union” is a blatant example—is one of just three cardinal sins that the ancient rabbis viewed as so grave that a Jew under compulsion to perform them must choose death instead. One might almost glimpse, between the lines of the Ten Commandments, a specific proscription of the practice: Thou Shalt Not Bow to Idols Even If Thou Callest It Yoga.

Part of the issue at stake, then, is how much of the old devotions and ideas inhere—or can be seen to inhere—in the stripped-out exercise that most today are familiar with. I believe that enough of them still do inhere to make religious Jews cautious. As we’ll see below, there is indeed an argument to be made against the practice on the basis of Jewish law (halakhah), and there may well also be broader philosophical reasons for caution.

II. Ascending to “the Yoga”

The better to understand the issues involved, let’s look at the literature of three yoga centers near my home in Washington, D.C., all within walking distance of the White House (and one of which advertises itself as having led sessions there). Each of them reveals aspects of modern “spiritual practice.”

One of the three refers to itself as “old-school,” with “classical Hatha roots.” The word Hatha is Sanskrit for “discipline of force.” As a type of yoga practice, it stresses, according to the Encyclopedia Britannica, “mastery of the body as a way of attaining a state of spiritual perfection in which the mind is withdrawn from external objects.” The form, dating back at least to the 11th century, includes the popular lotus position (padmasana) in which so many Buddhist and Hindu gods are pictured. Beyond mere exercise, Hatha’s true object “is to awaken the dormant energy (shakti) of Shiva that animates the subtle body but is concealed behind the gross human frame.” Shiva, one may recall, is a major Hindu god.

At the second area studio, we’re informed, one instructor “came to yoga, meditation, Eastern philosophy, energy medicine, and coaching through her own spiritual and healing journey.” Those wishing to train for a job teaching at this studio are asked to “describe how your lifestyle reflects philosophical teachings of yoga, or how you might like your lifestyle to do so in the future.” A $180 “book bundle” that is required reading for applicants includes the Hindu scripture Bhagavad Gita, or “Song of God.” In early classes, participants will be asked to “set an intention for your practice” that may include “offer[ing] up your practice to your highest Self or God.”

The third nearby center “invites” participants to take a break from their mobile phones in order “to maintain a sacred practice space.” This temple of sacred space “nurtures” community through “satsang, the ancient yogic tradition of coming together for meaningful connection to support the awakening of what is extraordinary in each of us.” Here the Britannica is again helpful in reminding us of the historical core of these less-familiar phrases. Satsang is at once “the assembly of true believers” and “a means of participating in the power of the divine Word that emanated from the hymns and songs of the Gurus [Hindu religious teachers].”

A recent workshop at this center, invoking Tibetan and Egyptian books of the dead and devoted to discovering “how other cultures view death and the afterlife as we explore what happens to the soul after it leaves the body,” pledges to recover for its participants “a past lifetime regression when you, too, could travel beyond time and space and retrieve aspects of your souls, and even skills you have lost in former lives.” The credentials sported by one teacher include authorship of a book of kabbalah purportedly endorsed by the Dalai Lama. Another instructor is “a practitioner of meditation and student of Buddhist and mystic teachings.” To train with these teachers, would-be yoga instructors will need to master the “spiritual aspects of asana (the poses),” as well as the “history and philosophy of yoga through study of ancient yoga texts.”

These three centers, respectively, emphasize aspects of yoga that relate to, first, mastery of the body and divine energy; second, directing attention to the self or God (as if the two were interchangeable); third, fostering community in the way that a religion gathers people together for a common spiritual purpose. From the literature of the three centers, one can perhaps begin to understand why, to some Jewish ears, yoga might sound more and more like what the Bible condemns as idol worship. Moreover, although one could easily imagine biblical-era idolaters toning their quads and abs via repeated bowings before Mammon or Ba’al, one would search in vain for a biblical judge, prophet, or lawgiver ready to issue a get-out-of-jail-free card to a Jewish idol worshipper pleading innocence on the grounds that he was merely seeking after his self or God—especially if “self” were capitalized.

IV. Exercise or Idolatry

One of the few contemporary Orthodox rabbis to tackle the yoga issue directly is Aryeh Lebowitz, director of the ordination program at Yeshiva University’s rabbinical seminary. Having tried yoga for exercise, Lebowitz was put off by the “sun salutations” and the standard bow that accompanies the phrase “namaste” and that in Hinduism means “I bow to the divine in you.” For him, even cursory research disclosed that everything in yoga comes from idolatrous practice, and that some studios even bring out statues of the gods for display during sessions. Hinduism, Lebowitz reminds listeners to his two 2015 talks on the subject (available at yutorah.org), isn’t some bygone faith; it’s very much alive today.

And yet, as Lebowitz ruefully admits,

It’s very difficult to get a psak [ruling] on yoga, because most of the rabbis you ask about yoga don’t know what it is. It may be completely permissible. [But] I just don’t know why [that would be].

Lebowitz proceeds to cite a number of halakhic prohibitions that in his view could legitimately apply to yoga. His discussion quickly becomes technical, but let me summarize the first two precedents:

First, the talmudic rabbis proscribed imitating the ways of the Gentiles, basing themselves on the biblical admonition, “Do not go according to their manners” (Leviticus 18:3). For the 14th-century Spanish rabbi Nissim of Gerona, this meant that any practices lacking clear logical explanations of their compatibility with Judaism were to be presumed guilty of being rooted in idolatry unless proved otherwise. That, Lebowitz comments, would certainly rule out a practice like yoga, which, as we have seen, is rooted in idolatry.

Second, another rabbinic ruling forbade even uttering the names of other gods (as in “Let’s meet near St. Vishnu Church”). Later rabbis disagreed over how to interpret this ruling and its details, but Lebowitz points out that, for a Jew, just showing up at a class in which a non-Jewish yoga instructor recites the name of an idol—the naan-and-butter of many a yoga posture—could be halakhically problematic.

To this same witness stand one might also summon the Lubavitcher rebbe, who in 1977 ruled against yoga practice, and the late halakhic authority Rabbi Chaim Yisroel Belsky, whose book On Alternative Medicine devotes two pages to yoga in which the author goes so far as to mock its wannabe Jewish adherents:

There are yoga classes all over the place and it is being advertised as being done in all purity; that there is absolutely nothing that was passed on from the old avodah zarah [idolatrous] practices from where it originated. People will tell you that yoga is, as they say today, “Super Glatt Mehadrin” [roughly, super-stringent kosher]. It is very hard to imagine that something like [yoga] is “Super Glatt.”

Many a yoga pose, Belsky continues, however much some contemporary rabbis might say it is simply exercise, is in reality “a supplication of the deity associated with that action—a type of worship through movement and posture.” To Jewish practitioners who have assured him that their yoga studios have been sanitized, which he takes as meaning that all traces of idols have been removed, he responds:

The truth, however, is that even if every little mantra was kashered [rendered kosher] with the most efficient kashering methods, and everything that seems forbidden was removed from it, it is still as if [a person] is copying the entire worship of the ba’al [idol]. It is as if someone would find the original book of this idol and follow the techniques from beginning to end—except they would delete any reference to the idol itself.

In brief, Belsky concludes, although Jewish yoga practitioners may feel, or protest, that they are merely strengthening themselves physically and mentally, “what they are doing is literally sacrificing themselves, sacrificing their Jewish souls.”

To be sure, there may be reasons, even halakhic reasons, to see yoga differently. Thus, Belsky in a footnote buttresses his argument with a negative ruling (in a related matter) by Rabbi Moshe Feinstein (1895-1986), a preeminent authority. But the late Rabbi Aharon Felder, a student of Feinstein, recorded in his memoir that he once asked Feinstein about yoga specifically. According to Felder, and contra Belsky, Feinstein averred that yoga represents mental preparation for subsequent idol worship rather than idolatry itself, and is therefore permissible.

Lebowitz also mentions a number of justifications that have been offered in defense of halakhic leniency. Some contend, for example, that yoga, rather than originating in the Hindu religion, actually predates Hinduism and can therefore be exempted from the disabling idolatrous identity that later accrued to it. Others take it as perfectly clear that Jews, and especially religiously observant Jews, practice yoga solely for purposes of exercise; that being the case, indicting its origins as idolatrous is utterly beside the point and carries no weight.

Indeed, this is probably the main argument made in favor of yoga by religious Jews. Along these lines, the Eretz Hemdah Institute for Advanced Jewish Studies in Jerusalem has issued a dispensation permitting yoga, and the same note has been struck more cautiously by an article in the science-and-Torah journal published by Yeshiva University’s Stern College for Women:

Today, there are several Jewish yoga studios which have removed the mantras, chanting, and definitely any icons from the yoga practice. One should be very aware of these considerations when choosing to practice yoga, and be careful to choose a safe place for this relaxing and healing practice.

V. What Counts as Idolatry

Where to draw the line in deciding what qualifies as idolatry?

In the Bible, the nearest approximation of a test case occurs in the book of Judges. Gideon has assembled an Israelite army to take on the Midianites. Wary that too mighty a platoon might delude itself into imagining that it, and not its divine backer, will have won the battle, God directs Gideon to bring his would-be troops to the water to hydrate. There, Gideon is instructed to dismiss anyone who kneels in order to drink; the only ones remaining are the 300 men who, impersonating dogs, lap up the water out of their hands with their tongues. The great medieval commentator Rashi explains: the kneeling majority were clearly idolaters, whose muscle memory knew the pose all too well.

Yoga is not a modern-day Gideonite test of fitness for fighting in God’s army. But even the assumption of a physical posture divorced from but directly referring to idol worship has its dangers. It’s not uncommon to hear rabbis of all denominations today inveighing against the metaphorical “idolatry” of narcissism or materialism. Practicing poses that still bear the names of a literally idolatrous practice is, however, surely closer than these metaphors to what the Bible prohibits.

Even if one takes the Talmud’s word for it that the evil inclination for idolatry was once actually and successfully contained, it would be the height of arrogance to assume that our own postmodern culture and technology have immunized us from idolatrous urges—including the core idolatrous urge to elevate physical conditioning to the level of a spiritual practice, to pursue (in the Britannica’s paraphrase of Hatha discipline) “mastery of the body as a way of attaining a state of spiritual perfection.”

This may be the heart of the religious problem with contemporary yoga and its culture. Even if one practices in a studio free of idols, the core of contemporary yoga culture promotes an idolatrous replacement of God with one’s body as the ultimate focus of one’s devotional attention. And here the pulpit rabbis inveighing against the “idolatry of narcissism” make a perhaps unintended connection—one that, relevant for all Jews, is especially so for religiously observant ones. From this perspective, the physical performance by such Jews of the rites demanded by an idol they don’t believe in can be seen as just the latest stage in the long-term evolution of a deadly spiritual impulse.

The Torah and centuries of rabbinical exegesis offer myriad pieces of advice for Jews who want to clear their minds, focus their attention appropriately on God, and be present in the wondrously beautiful world that God has given to humanity. Prayer, for one thing. Study of Jewish texts, for another. Contemplating the miracle of Jewish survival and doing deeds to preserve it, for a third. The list goes on. As for idolatry, with apologies to Romeo and Juliet, by any other name it would smell as foul.