Yevamot 4B

שמע מינה לאפנויי. וגבי ציצית נמי, איבעית אימא ⁠— משום דמוכח, ואיבעית אימא ⁠— משום דמופנה.

Learn from this that this phrase is free to teach an additional halakha. And with regard to tzitzit 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.

איבעית אימא משום דמוכח ⁠— דאם כן לכתביה רחמנא גבי פרשת ציצית, למאי הלכתא כתביה הכא? ואיבעית אימא משום דמופנה ⁠— מכדי כתב: ״ובגד כלאים שעטנז לא יעלה עליך״, ״לא תלבש שעטנז״ למה לי? שמע מינה לאפנויי.

The Talmud 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 God write this verse by the portion of tzitzit (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 should there come upon you a garment of diverse kinds mingled together” (Leviticus 19:19). Why, then, do I need the verse: “You should 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.

הני מצרך צריכי, דאי כתב רחמנא ״לא יעלה עליך״, הוה אמינא: כל דרך העלאה אסר רחמנא, ואפילו מוכרי כסות, כתב רחמנא ״לא תלבש שעטנז״, דומיא דלבישה, דאית ביה הנאה.

The Talmud rejects this explanation: Both of these verses are necessary, as, had God written only: “Neither should there come upon you,” I would say that God 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, God writes: “You should 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.