Parashas Metzora · Passuk 14:47
Chabad.org — English translation + Rashi
Torah Temima points to Toras Kohanim.
English: “And whoever lies down …” — I have only [the case of] one who lies down and eats; whence [do I know the law for] one who neither lies down nor eats? The verse says “he shall wash his garments,” which expands. If so, why does it say “lies down” and “eats”? To give a measure for lying down equal to the measure of eating — and how much is the measure of eating? The time it takes to eat a peras.
Duration threshold
Chazal set the minimum time of presence that triggers garment-washing at the duration of eating a half-loaf (peras).