The Torah commands us not to wear a garment made of wool and linen, as it states: “You shall observe My statutes: you shall not mate your animal with a different species, you shall not sow your field with two kinds of seed, and a garment of mixed kinds, sha’atnez, shall not come upon you” (Vayikra 19:19). It also states: “You shall not wear sha’atnez, wool and linen together” (Devarim 22:11).
The wool included in this prohibition is sheep’s wool. Male sheep are called rams, and females are called ewes. The fleece of other animals is not included, because it is not called simply “wool” but is identified by a qualifying term. Thus, the prohibition does not apply to camel wool, goat wool (such as cashmere), rabbit wool (such as angora), or alpaca wool. In practice, from antiquity to the present, most of the world’s wool has come from sheep, which naturally produce abundant, high-quality fleece and are readily domesticated.
Flax is a plant with a single long stalk containing fibers that can be made into strong thread. With special processing, these fibers can be spun into fine thread and woven into attractive white garments. The prohibition of sha’atnez applies specifically to flax and not to fibers derived from other plants, such as hemp or cotton. In earlier times, most clothing was made of wool or linen; some therefore maintain that when the Torah uses the word “garment” without qualification, it refers to a garment made of wool or linen (Menaḥot 39b).
The prohibition of sha’atnez applies to wearing a garment containing both wool and linen. It does not prohibit wearing two separate garments, one made of wool and the other of linen. One may therefore wear wool pants with a linen shirt, or a wool robe fastened with a linen belt. As long as the wool and linen garments are not joined by sewing or a permanent knot, there is no prohibition (below, 6).
The prohibition applies to wearing garments containing wool and linen, not to making sha’atnez fabric for other purposes. It may therefore be used as a decorative wall hanging, as a parokhet for an ark, or to make a cloth purse or tent. It may also be used for burial shrouds, since the deceased are exempt from mitzvot. Likewise, one may manufacture sha’atnez garments for non-Jews, provided there is no concern that they will come into the possession of a Jew who might mistakenly wear them.
