הלכה אויף דברים 13:13

We do not blow with a shofar of idolaters at the outset. But if one did blow [with one], he has fulfilled [the commandment]. And if one blew [with a shofar] of a condemned city (eer hanidachat), he has not fulfilled [his obligation. Regarding] a stolen shofar with which he has blown, he has fulfilled [the obligation]. For the commandment is only listening to the sound — even though he did not touch it and did not raise it up, the listener has fulfilled [it] — and there is no law of theft with sound. And likewise should one not blow with the shofar of a burnt offering; but if he did blow [with it], he has fulfilled [the obligation]. For there is no law of misappropriating [the sacred] with sound. And if you say, "Did he not derive pleasure from listening to the sound"; [the answer is] that the commandments are not given for pleasure. Hence, one who has vowed not to derive pleasure from the shofar is permitted to blow the blow of the commandment with it.

The threads used for the fringes, whether white or blue, must be spun with the express intention of being made into fringes. They are not made of wool caught by the thorns where the sheep lie down, nor from the wisps that are plucked from the animal, nor from the remainders of the warp left by the weaver on the selvage of the cloth, but only of the wool-shearing or of flax. Nor are the fringes to be made from wool that has been part of the proceeds of a robbery, or that comes from a city that has gone astray (Deuteronomy 13:13-18), nor from wool of beasts set apart for sacrifice. If such wool has been used for fringes, the latter are unfit for use. If a person prostrates himself in worship before a beast, its wool is unfit for use as fringes. But if he so prostrates himself before planted flax, it is fit for use, because its character has been changed.^**The flax has been turned into linen.

None of the cities of escape is adjudged a seduced city, as it is said: "Within any of thy gates" (Deut. 17.2); nor is Jerusalem adjudged a seduced city as it was not divided among the tribes. A buffer city must not be adjudged a seduced city, lest the idolaters enter through it and destroy Eretz Ysrael. A single tribunal should not adjudge three cities, one alongside the other, seduced cities, but if they be far apart it may be done.⁶Sifre, Deut. 17; Sanhedrin, 2a; Ibid. 16a-b; Baba Kamma, 72a C.G.