The list of Torah mitzvot continues with the negative commandments, those things that we must abstain from and not do. There are a total of 365 negative mitzvot. The first 45 relate to various prohibitions associated with idolatry.
Summary: The first negative commandment is not to even consider the thought of idolatry or that there are any other gods. There are many more idolatry-related prohibitions that follow. These include not making idols (#2), not to bow down to them (#5), or worship them in any other way (#6), not to make idolatrous pillars (#11) or prostrating stones (#12), or planting trees for worship (#13). Also are prohibitions of prophesying in the name of a false god (#26) or to listen to such “prophecies” (#28), or to follow any customs or laws of idolaters (#30). Relatedly, the next eight mitzvot have to do with prohibiting all kinds of black magic and fortune-telling. Divination, witchcraft, sorcery, and necromancy are all strictly forbidden. There are another seven negative mitzvot which, according to the Rambam, are associated with idolatry or adopting inappropriate foreign customs. These include cross-dressing (#39-40), tattooing (#41), wearing garments with wool and linen intertwined (sha’atnez, #42), shaving off the hair around the temples and beards (#43-44), and self-mortification, specifically cutting into flesh (#45).
There are shatnez-testing services and events in Jewish communities around the world. A garment can be checked under a microscope to determine if it has a prohibited mixture of fabrics.
Insight: One of the Torah’s most mysterious mitzvot is that of sha’atnez, the prohibition of wearing garments that have wool and linen combined. What is the problem of weaving together wool and linen? Some suggest that this prohibition is similar to that of not consuming meat and dairy products together. Meat is representative of death and bloodshed, while milk is a liquid of life. They have completely opposing spiritual energies, and thus should not be mixed together. Similarly, wool comes from animals while linen comes from plants. They have contradicting spiritual energies and should not be combined. On a deeper, mystical level, the Arizal (Rabbi Itzchak Luria, 1534-1572) explained that it all goes back to Cain and Abel. Recall that each of the brothers brought an offering to God, but Cain’s was inferior. God turned to Abel, and this angered Cain, eventually leading to the first murder. The Arizal states that Cain had brought an offering of linen, while Abel had brought an offering of wool (see Sha’ar HaMitzvot on Kedoshim). Henceforth, this “mixture” of wool and linen became spiritually problematic. By separating between these two fabrics, we accomplish a tikkun, a spiritual rectification for that great sin at the beginning of civilization. The Arizal’s predecessor, the Ramak (Rabbi Moshe Cordovero, 1522-1570) pointed out that sha’atnez (שעטנז) is an anagram of satan oz (שטן עז), and this mitzvah has a particularly strong ability to ward off and combat evil forces.