The prohibition of eating the gid hanasheh, the sciatic nerve, of kosher mammals, is a Biblical commandment derived from the story of Jacob’s struggle with the angel, where it is written: “Therefore the children of Israel may not eat of the gid hanasheh, which is upon the hollow of the thigh, unto this day; because he touched the hollow of Jacob’s thigh in the gid hanasheh.”1

After wrestling with an angel all night, Jacob emerges victorious. During the struggle, the angel dislodges Jacob’s sciatic nerve. To commemorate this event, Jews are forbidden from eating the sciatic nerve of any animal.

Read: Jacob Wrestles With the Angel

In practical terms, this prohibition means that certain cuts of meat from the hindquarters of an animal are not kosher. Nikkur, the process of removing the sciatic nerve and other forbidden fats from these cuts, is labor-intensive and requires extensive training. As a result, in many communities, the hindquarters are sold to the non-kosher market.

Read: 22 Kosher Facts Every Jew Should Know

The Kabbalists attribute a deeper spiritual meaning to this prohibition. The sciatic nerve, located at the thigh, represents the potential for sexual temptation that rests within us. Its very name, nasheh, means “to forget,” because once it has been aroused, all rational thinking and religious scruples are left far behind. The only way to ensure victory over our most base desires is to steer clear of compromising situations and thoughts in the first place.

Read: Why Don’t We Eat the Sciatic Nerve?