The most mysterious category of commandments is the group designated as "Chukim", i.e., Divine statutes that, at least at first glance, lack rationales for their significance and importance. An exemplary "Chok" is contained in Devarim 22:11, when the Tora instructs, "Do not clothe yourself in Sha'atnez, wool and linen together." One naturally wonders why the Tora would be concerned about the specific fibers employed to create cloth, as long as they have not been stolen, dedicated to idolatry, etc.
The prohibition against wearing garments that are Sha'atnez is viewed by RaMBaN as another of the Mitzvot Mevuarot (commandments that are being clarified and explicated) by Moshe in Mishna Tora (a name for Devarim based upon its verse in 17:18) since the formulation in 22:11 is both a repetition, as well as an expansion, of VaYikra 19:19: "... and a garment of Sha'atnez mixtures should not go up upon you." Overt differences between the two verses are the use of the term "garment" in VaYikra (to the exclusion of the fibers being placed together without being woven into a single piece of cloth) and the specification in Devarim of wool and linen. (The verse in VaYikra suggests that mixtures of any and all fibers would be prohibited.) Yet aside from the clarification of details, it must also be noted that when a Mitzva is discussed in more than one place in the Tora, greater importance will be attributed to such a commandment, begging the question further regarding what Sha'atnez is coming to teach us.
The prototypical nature of Sha'atnez as a practice that due to its rational opacity will be an object of curiosity and even derision is suggested by RaShI on VaYikra 18:4 when he explains why the Tora has to specifically adjure the Jews to observe Chukim by invoking at the end of the verse the phrase "I am the Lord your God": "The Evil Inclination will present arguments challenging these commandments, "Why should we keep them?" as will the nations of the world, regarding a) the prohibition against consuming pork, b) the wearing of Sha'atnez, and c) ritual purification by means of sprinkling the mixture of ashes from a red heifer and water. Therefore it is stated (at the end of the verse)"I am God" and I have decreed these commandments upon you. Consequently you are not permitted to be exempt from them." (RaMBaN quotes a similar source in his commentary on Beraishit 26:5.)
Whereas in the Dvar Tora for Parshat VaEtchanan "Seeing Judaism Through the Eyes of Others", R. Yaakov Zvi Mecklenberg's and Rabbeinu Bachaye's interpretations for Devarim 4:6 were cited, both explaining how the observance of Chukim, supposedly including the prohibition of Sha'atnez, by the Jews wins for them admiration in the eyes of members of other nations, a diametrically opposite position appears to be assumed by RaShI and RaMBaN in the commentaries cited above.(*)
However, it is possible to reconcile these two apparently contradictory sources. When Satan/Yetzer HaRa and the nations of the world are described as challenging us regarding our Mitzva observance, is this due to hostility or mere curiosity and intellectual investigation? While the purpose of the Evil Inclination is generally thought to be one of entrapping and misleading us, being forced to overcome personal skepticism can lead to greater understanding and spiritual fulfillment. Perhaps this is the intent of RaShI's comment on Devarim 6:5, when he states that the meaning of the plural "hearts" in the phrase, "And you shall love the Lord, your God with all of your hearts" is "with both of your Yetzers," reflecting the paradoxical reality that even the Evil Inclination can be enlisted in the service of the Divine.
As for Devarim 4:6, are we to assume that non-Jews, when simply seeing what they perceive to be strange behavior on the part of observant Jews, will automatically attribute to them deep wisdom and understanding, or must such a positive evaluation on their parts be earned by us, by means of open and honest discussion and explanation? When an individual is questioned by a co-worker or fellow student as to his/her dietary habits or other aspects of his/her Jewish lifestyle, how important is it to be able to present explanations for what one is or is not doing? The debate regarding the existence and comprehensibility of reasons for all commandments, including Chukim, is summarized in this week's Parsha by RaMBaN in his commentary on Devarim 22:6. The view espoused by RaMBaM and RaMBaN, i.e., that it is altogether appropriate to seek out such rationales for all commandments, would in turn equip us to help effect a Kiddush HaShem in the eyes of others by demystifying our rituals and practices, and hopefully bringing them to the recognition that Deracheha Darchei Noam VeChol Netivoteha Shalom (its ways are ways of pleasantness, and all of its paths are peace.)
In conclusion, let us consider one rationale (there could be multiple reasons and explanations for any and all Mitzvot) for the prohibition of Sha'atnez, appearing in Midrash Tanchuma, Beraishit #9. "And Kayin brought from the fruits of the earth ..." The Rabbis interpreted that this was flax (from which linen is derived). "And Hevel also brought from the firstlings of his sheep and of the fattest of them." For this reason wool and linen were prohibited. Chizkuni (R. Chizkiya ben Manoach Chizkuni, Provence, ca. 1250) on Devarim 22:11 expands upon the Midrash's theme: "Since a tragedy resulted from these two substances, they were prohibited to be used simultaneously." Rather than contemplating the mystical properties of these two fibers and how they somehow upset the Divine Order of Creation, the Rabbis of the Midrash have attributed to the commandment an ethical teaching by asking us to associate with Sha'atnez the dangers that arise as a result of fierce competition and rivalry, even LeShem Shamayim (for the sake of Heaven), i.e., both brothers were striving to show their devotion to the Divine. The commitment to continually refine how we treat not only our siblings, but all fellow human beings, should certainly contribute to impressing others with the wisdom and understandings of our beliefs, even as it might mollify our severest critic, the Yetzer within each of us.
Shabbat Shalom!
(*)The earlier sources that serve as the basis for RaShI's and RaMBaN's commentaries are the Midrash Halacha Sifra on Achrei Mot 9:13 and Yoma 67b. With regard to the Talmudic source, some versions of the Gemora only refer to the Satan or Yetzer HaRa, omitting any mention of the nations of the world. While this is most likely due to censorship --- the censors perceiving that this was an attack upon non-Jews, implying their intolerance --- it would be interesting to speculate whether the original sources did not include a reference to the nations of the world, and it was something that was added at a later point. The syntax in RaShI's words lends itself to view the phrase "as will the nations of the world" as an afterthought or subsequent addition.