Learn from this that this phrase is free to teach an additional halakha. And with regard to ritual fringes as well, there is a particular reason to derive a homiletic interpretation from the juxtaposition of verses. If you wish, say that it is because it is evident from the context, and if you wish, say instead that it is because this verse is free for this inference.

The Gemara elaborates: If you wish, say it is because it is evident; as, if it is so that no inference should be drawn from the adjacent verses, let the Merciful One write this verse by the portion of ritual fringes (Numbers, chapter 15). With regard to what halakha did the Torah write it here? Clearly, the Torah is teaching a halakha from the adjacent verses. And if you wish, say it is because this verse is free, since the Torah has already written: “Neither shall there come upon you a garment of diverse kinds mingled together” (Leviticus 19:19). Why, then, do I need the verse: “You shall not wear diverse kinds, wool and linen together” (Deuteronomy 22:11)? Learn from this that the verse is free for the derivation of a homiletic interpretation from juxtaposed verses.

The Gemara rejects this explanation: Both of these verses are necessary, as, had the Merciful One written only: “Neither shall there come upon you,” I would say that the Merciful One prohibits every manner by which a garment of diverse kinds comes upon you, and this applies even to sellers of coverings, who do not wear the garments but merely rest them on their shoulders. Therefore, the Merciful One writes: “You shall not wear diverse kinds,” to teach that the prohibition applies only in cases similar to wearing, which provides benefit and does not simply involve placing the covering upon oneself.

And had the Merciful One written only: “You shall not wear,” I would say that this means specifically wearing, which provides significant benefit, both warmth and adornment, but merely placing a garment of diverse kinds upon oneself is not prohibited, even if one is warmed by the clothing. Therefore, the Merciful One writes: “Neither shall there come upon you.”

The Gemara challenges: In any case part of the verse is superfluous, as, if so, let the Merciful One write only: “You shall not wear diverse kinds.” Why do I need the addition of “wool and linen”? The definition of diverse kinds in clothing is already known from another source.

How so? Since it is written: “Neither shall there come upon you a garment of diverse kinds mingled together” (Leviticus 19:19), and the school of Rabbi Yishmael taught: Since the word garments is stated in the Torah unmodified, without stating from what materials those garments were made, and the verse specified in one of its references to garments, in the context of the halakhot of ritual impurity of leprosy: “A woolen garment or a linen garment” (Leviticus 13:47), the following conclusion can be drawn: Just as when the Torah mentions a garment in the case of leprosy it is referring to one made of wool or linen, so too, all garments mentioned in the Torah are those made from wool or linen. Other fabrics are not classified as those used for garments. If so, why do I need the phrase: “Wool and linen” that the Merciful One wrote with regard to diverse kinds? Learn from this that the superfluous passage is free.

The Gemara raises a difficulty: But the verse is still necessary, as it could enter your mind to say that it is referring only to placing a garment on oneself, which does not provide great benefit; however, with regard to the actual wearing of a garment, which entails great benefit, the Merciful One prohibits wearing any two types together. Therefore, the Merciful One writes “wool and linen” with regard to wearing garments of diverse kinds as well.

The Gemara responds: If so, let the verse be silent and refrain from mentioning wool and linen at all, and the halakha that only wearing wool and linen together is prohibited can be derived by means of a verbal analogy between the terms “diverse kinds” (Deuteronomy 22:11), and “diverse kinds” from placing a covering of diverse kinds upon oneself (Leviticus 19:19). The repetition of wool and linen must be coming to teach that one should derive a homiletic interpretation from these juxtaposed verses.

The Gemara asks: And according to that which the school of Rabbi Yishmael taught, that the mention of wool and linen is superfluous and teaches that they are not prohibited in the case of ritual fringes, the reason is that the Merciful One specifically writes wool and linen. From here it may be inferred that if that were not so, I would say that the Merciful One prohibits a mixture of diverse kinds in ritual fringes. Can it be considered that this is the case? But isn’t it written: “That they make themselves fringes on the corners of their garments” (Numbers 15:38)?

And the school of Rabbi Yishmael taught: All garments mentioned in the Torah are of wool or linen, and the Merciful One says, with regard to ritual fringes: Prepare it with a sky-blue dye, and a sky-blue dyed thread is prepared from wool. The Torah explicitly commands that at least one woolen thread of sky-blue dye must be tied even to a linen cloth, which proves that diverse kinds are permitted in the context of ritual fringes. The Gemara establishes the previous claim: And from where is it derived that the sky-blue thread is made of wool? From the fact that the Torah specifies that one of the strands of the priestly garments was made of shesh, which means linen, this indicates that the other threads, including the sky-blue thread, are from wool.

§ Returning to the question, the Gemara explains that the mention of wool and linen is necessary, as it could enter your mind to state an argument in accordance with the opinion of Rava. As Rava raised a contradiction from the following verse: It is written: “That they make themselves fringes on the corners of their garments” (Numbers 15:38). The phrase “the corners” indicates that it must be from the same type of thread as the corner, i.e., the threads of the fringes must consist of the same kind of material as the corner of the garment. And yet it is written: “Wool and linen” (Deuteronomy 22:11), which indicates that ritual fringes may be prepared from only those materials and no others.

How so? How can this contradiction be resolved? Fringes made of wool and linen fulfill the obligation of ritual fringes whether the clothing is of the same type of material, i.e., wool or linen, or whether it is not of the same type of fabric. Conversely, with regard to all other kinds of material, if the ritual fringes are of the same kind, e.g., silk fringes on silk clothing, they fulfill the obligation, but if the cloth is not of the same type, they do not fulfill the obligation of ritual fringes. Consequently, were it not for the phrase “wool and linen,” it would have been necessary to prepare ritual fringes from the same material as the garment itself, even when using wool or linen.

The Gemara asks: But the tanna from the school of Rabbi Yishmael does not maintain in accordance with this opinion of Rava, since that tanna holds that there is no obligation to place ritual fringes on clothing that is not made of wool or linen. The reason is that when the Torah speaks of garments it is referring exclusively to clothes made of wool or linen. Consequently, Rava’s interpretation with regard to different types of material does not apply to the opinion of the tanna from the school of Rabbi Yishmael.

The Gemara responds: It is nevertheless necessary to state: “Wool and linen,” as it could enter your mind to say, in accordance with the inference of Rava, that the phrase “the corners” indicates that it must be from the same type of thread as the corner, but in a different manner: This is what the Merciful One is saying: Prepare for it wool fringes for a wool garment and linen fringes for a linen garment, and when you prepare wool fringes for wool clothing, dye it sky-blue. However, if you prepare wool fringes for linen garments or linen for wool clothing, you need not include a sky-blue thread. Therefore, the Merciful One states: “Wool and linen,” which teaches that one fulfills the obligation of fringes even with wool fringes for a linen garment or linen fringes for a woolen one.