Shatnez is a prohibition in Jewish law against wearing a garment made from a mixture of wool and linen. The Torah states that “You shall not wear shatnezwool and linen together” (Deuteronomy 22:11), and this prohibition is repeated in the Talmud (Shabbat 110a).
There are a number of reasons why shatnez is prohibited. One reason is that it is a mixture of two different types of fibers, which is considered to be a form of idolatry. Another reason is that shatnez is uncomfortable to wear, and it can cause skin irritation.
