Talmud su Levitico 13:48

“Only wool and linen can become impure by mold disease,” for it is written (Lev. 13:47) “on woolen cloth or on linen cloth.” I could think they can become impure whether dyed or natural; the verse says “woolen cloth or linen cloth.” Just as linen is in its natural state so wool must also be in its natural state¹²Sifra Paršat Nega‘im 13(3–4). It seems that the name of פשתים was used only for undyed linen cloth; dyed cloth had other names.. I might exclude what was dyed by humans but not what was dyed by nature; the verse says (Lev. 13:48): “For the linen and for the wool¹³The implied definite article restricts this to what is certainly called linen and woolen cloth, not, תכלת, ארגמן, תולעת שני, etc. The Babli (Bekhorot 17a) quotes a baraita using the same verse to exclude wool from kilaim of sheep and goats.”, just as linen is white so wool has to be white.