The text seems to not only tells us how to be Jewish, but also defines what Judaism is not.
We erect a key barrier between ourselves and certain behaviors, and we do it with circumcision, mul. This word is used in the text to teach us the foundational exclusions for Jewish behavior: male circumcision (G. 17:11, L 12:3), as well as circumcising our hearts (D. 10:16). Circumcision, mul, reminds us to act in conscious self-awareness that what we do with our physical bodies also changes our spiritual souls. So the word Mul is about establishing an enduring opposition to certain behaviors and actions.
We see this in the text because the entire Book of Deuteronomy, Moshe’s speech to the people, is set in a place called mul Peor (D. 3:29, 4:46). Why?
For starters, mul does not necessarily refer to a place one can find on a map. There are Hebrew words that tell us about proximity – kneged or al yad. These can mean “opposite” or “nearby” or “next to.” But these are not the words used in this case: the Torah uses mul instead.
Why? Because Peor is not necessarily a place at all! Peor is instead, a kind of behavior.
The people profaned themselves by whoring with the Moabite women, who invited the people to the sacrifices for their god. The people partook of them and worshiped that god. Thus Israel attached itself to Baal-Peor. (N. 25:1) … So Moses said to Israel’s officials, “Each of you slay those of your men who attached themselves to Baal-Peor.” (N. 25:5) … Because of the affair of Peor and because of the affair of their kinswoman Cozbi, daughter of the Midianite chieftain, who was killed at the time of the plague on account of Peor. (N. 25:18) … Yet they are the very ones who, at the bidding of Balaam, induced the Israelites to trespass against G-D in the matter of Peor (N. 31:16)
Peor is not necessarily defined in the Torah as a place, nor is it even necessarily an idol. Peor is the glorification of hedonism for momentary pleasure – and acting in this way profanes marriages and all holy relationships. The cost of Peor is the corruption of our very souls, and the consequential withering away of our potential to productively connect with a spouse or with G-d.
And thus Peor is the Achilles Heel of the Jewish people. This is why the word is first mentioned when Balaam first recognizes that the Jewish people excel because of our families (“How goodly are your tents, O Jacob!” (N. 24:5)). Balaam says these words, the Torah tells us, at the peak of Peor, which overlooks the wasteland. (N. 23:28) When seen from the “peak of Peor,” from the perspective of wanton hedonism, the superpower (and kryptonite) of the Jewish people is revealed to Balaam. Balaam uses that knowledge to corrupt the people with the daughters of Moab. The act of Cozbi and Zimri (N. 25:6-15) profanes all that could be holy. It is Peor: the negation and corruption of Jewish mul, circumcision, and the self-control that is supposed to come from it.
To this day, Jews have wrestled with Peor, with a “Dark Side.” As holy and pure as our families can be, the antithesis remains a temptation, which is why some prominent (albeit usually non-observant) Jews embarrass the rest of us by behaving very badly indeed, promoting and exploiting the desire for Peor in the world today. That Dark Side must be cut away, circumcised, mul.
In the place where Moshe makes his Devarim speech, he stands fundamentally opposed to everything skin-deep, to everything Peor and hedonistic in nature. Moshe is making a core statement: life is more important than the momentary pursuit of passing pleasure. Holy relationships with our spouses and with G-d require us to apply the lessons of circumcision to all of our behavior
And when Moshe dies? The Torah tells us that Moses is buried in the valley in the land of Moab, mul Beth-Peor. (D. 34:6). Moses’ principles extend both in his life and in perpetuity, for even when dead and buried, Moses embodies the opposition to profaning holy relationships.
We must not annihilate our infinite spiritual potential by indulging fleeting physical desires.
P.S. The word Peor contains the word “skin” within it, suggesting that acting with Peor is making decisions using only superficial, skin-deep motivations and thought.