Dear Rabbi,

I noticed something interesting in the congregation I attend. Virtually everyone’s prayer shawl, the tallit, is made of wool.

Is there any specific reason why I do not see any silk or cotton prayer shawls?

Answer:

Great observation! There is indeed a good reason for this.

In the Talmud, there is an opinion that one is Biblically obligated to affix tzitzit, the ritual fringes that are on the corners of the prayer shawl, onto a wool or linen garment only.

This is learned from a verse where it states in regards to a specific law involving clothing,1 “a woolen garment, or on a linen garment.”2 From here some learn that when it says “garment” in the Bible in the context of a commandment, it is referring specifically to wool and linen garments. Therefore, the commandment to place fringes on a four-cornered garment—“You shall make yourself twisted threads, on the four corners of your garment with which you cover yourself”—is referring specifically to a wool or linen garment.3

According to this tradition, placing fringes on garments made of other materials, such as silk, is a rabbinical requirement, not a Biblical one.4

In his gloss on the Code of Jewish Law, Rabbi Moshe Isserles, known as the Rema, rules that garments of all fabrics are equally Biblically required to have fringes.5

Nonetheless, it is preferable to wear a prayer shawl that is made of wool,6 since it is Biblically required according to all opinions.7