Severity
1. The Torah prohibits putting on a garment with a mixture of sheep wool from a ram or ewe and linen. This is derived from the pesukim, “ובגד כלאים שעטנז לא יעלה עליך ” (ויקרא י"ט י"ט ) and “לא תלבש שעטנז צמר ופשתים יחדיו ” (דברים כ"ב י"א ).
2. Transgresses every moment. One who is wearing shaatnez violates a lo saaseh every moment he is able to take it off but does not do so (רמב"ם פ"י כלאים ה"ל ).
3. Chok. Although the issur of shaatnez is a chok, as indicated in the posuk, “את חקתי תשמרו כו' ובגד כלאים שעטנז לא יעלה עליך ” (ויקרא שם ), some reasons have been given. One of these reasons is that the avodoh zoroh priests in Mitzrayim would wear garments made of wool and linen. Hashem prohibited us from wearing these garments to distance us from avodoh zoroh (רמב"ם מורה נבוכים ח"ג פל"ז, רמב"ן עה"ת פ' קדושים, חינוך מ' תקנ"א ).
4. There is a Midrash which says that it was “difficult” [kaveyochol] for Hashem to redeem Klal Yisroel from Mitzrayim since they were uncircumcised, had certain hairstyles, and wore shaatnez just like the Mitzrim (ויק"ר פכ"ג ב'). We must strengthen and learn about the issur of shaatnez and become more aware of its severity. Doing so will naturally help us avoid this issur and speed the geulah.
5. Holds back tefillos. Besides for violating an issur, one who wears shaatnez prevents his tefillos from being accepted. This is because he looks like an avodoh zoroh priest to the malach who takes Klal Yisroel’s tefillos (ריקאנטי פ' קדושים ). This applies even to one who wears shaatnez unintentionally (ספר שלמי ציבור למהרי"ט אלגאזי דיני ההכנות לתפילה סי' ג', קב הישר פמ"ו, יסוד ושורש העבודה שער הכולל פי"ח ).
Types of Fabric Included in the Issur
6. Types of wool. The only wool that makes a shaatnez mixture is wool from male or female sheep. Camel wool, angora rabbit wool etc. are not included in the issur of shaatnez.
7. Linen. Only linen is part of the issur. Other similar fabrics, e.g., hemp, cotton, etc. are not linen and may be combined with wool.
Not Wearing Any Wool Clothes
8. Due to the severity of the issur of shaatnez, some people are machmir and do not wear any wool clothes. Several Acharonim write that a G-d-fearing person should not wear wool clothes since it is common to find linen threads in them (חכמ"א כלל ק"ו אות כ"ה ). One who is machmir on himself not to wear wool out of fear of violating the issur of shaatnez is called “holy” (שו"ת חת"ס או"ח סי' ט"ו ).
9. Bekeshe. Thousands upon thousands of Chassidim today wear a bekeshe on Shabbos; many do not know why. The minhag stems from a concern of violating shaatnez with wool clothes. During the week, people did not wear wool, so Chassidim did not feel the need to only wear silk. On Shabbos, however, when people wore elegant clothes, many of which were wool, Chassidim specifically wore silk clothes to preclude any fear of shaatnez. They also wore silk or fur coats. Some wore silk or materials other than wool even during the week for the same reason.
Dressing a Child in Shaatnez
10. One may not dress a child in shaatnez, even if he is very young and does not have daas, based on the issur of “feeding by hand” [“sofinon beyodayim”] (מנ"ח מ' תקנ"א סק"ה, שו"ת עונג יו"ט סי' צ"ו ). Thus, children’s – and even infants’ – garments must also be checked for shaatnez. If the child dresses himself, there is no issur of “feeding by hand,” but shaatnez is still ossur due to chinuch.
Some Principles of the Issur of Shaatnez
11. Most of the detailed halochos of shaatnez are only relevant to shaatnez checkers and poskim who specialize in shaatnez. Here, we will focus mainly on halochos relevant to the general public.
Forms of Shaatnez
12. A garment [“beged”] is a cloth woven from threads. A thread [“chut”] is a group of fibers spun together into a strand. Fibers [“sibim”] are thin filaments which come from animals, plants, or synthetic materials.
13. Combination of fibers in a thread. The issur of shaatnez has several forms. If a thread is spun from both wool and linen fibers, we do not apply the rule of bitul berov since the combination itself is the issur (תוס' נדה ס"א: ד"ה בגד, ט"ז סי' רצ"ט סק"א ). Thus, even if the thread is mostly made up of wool and partially of linen, the entire thread is ossur. One may not make a garment from it or use it to sew a garment.
14. Combination of threads in a garment. If a garment contains several whole wool threads, one may not sew it with linen threads, even if it is made mostly of a different material (שו"ע סי' רצ"א ס"א ). We do not say the wool threads are botul in the other material, as we will below (19) since whole threads are significant and are not botul. Similarly, if a garment is woven with silk threads lengthwise and linen threads widthwise, even if the majority is silk, it may not be sewn with wool since the linen threads are not botul (סמ"ג ל"ת רפ"ג, שו"ת נודב"י מהדו"ת סי' קפ"ו ).
15. Combination of fabrics in a garment. If a piece of wool fabric was sewn to a piece of linen fabric using a thread of a different material, everyone agrees the garment is ossur since the wool and linen are connected by the stitching (ש"ך סי' ש' סק"ב ).
16. If there is a piece of fabric of a different material separating the wool and linen and the stitching goes through all three pieces, some say that all poskim would agree it is ossur (יוסף אומץ פ' המצוות עמ' 342, מו"ר בספרו מלבושי ישע פ"ג הע' ל"א ).
Garment with Wool and Linen Stitching
17. Wool and linen in a thread. A garment made of silk or cotton, for example, sewn with a shaatnez thread, i.e., a thread that has wool and linen interwoven or spun together, is shaatnez and ossur (שו"ע יו"ד סי' ש"א ס"ג ) mideoraiso (מו"ר הגרי"י בלויא, מלבושי ישע פ"ג הע' י"ג ).
18. Wool thread and linen thread. If a cotton garment has some wool stitching and some linen stitching but the wool threads and linen threads do not touch, some say it is shaatnez and ossur (רמב"ם פ"י כלאים ה"ט, סתימת השו"ע סי' רצ"ט ס"ב ), others say it is muttar (ר"ש כלאים פ"ט מ"ט, רמ"א ). The minhag is to be meikel (טור סי' ש"ט, ערוה"ש סי' ש' סי"ב וי"ד, חכ"א כלל ק"ו הי"ט ) but a G-d-fearing person will make sure his clothes are muttar according to all poskim (חכ"א ).
