TT #640 · Parashas Ki Seitzei · Seventh Aliyah · Passuk 25:04
You shall not muzzle an ox while it is threshing.
Torah Temimah points to Bava Metzia 89a.
TT lemma: לֹא תַחְסֹם שׁוֹר.
English: Since every matter is included in the prohibition of muzzling, why does the Torah write ‘ox’ rather than simply ‘do not thresh while muzzled’? To equate the one who muzzles with the one who is muzzled and the one who is muzzled with the one who muzzles: just as the one who muzzles (a human worker) may eat from attached produce, so the one who is muzzled (the animal) may eat from attached produce; and just as the one who is muzzled may eat from detached produce, so the one who muzzles may eat from detached produce.
Hekesh (equation of the one who muzzles with the one who is muzzled) — not a formal named middah of the 13; the mutual rights of worker and animal are derived.
The verse teaches mutual rights: both the working animal and the human laborer may eat from the produce they are processing, whether still attached or already detached.