"Therefore the sons of Israel do not eat the sinew which shrank." Targum Pseudo-Jonathan (Genesis 32:33) preserves the origin of one of the oldest kosher laws — the prohibition against eating the gid ha-nasheh, the sciatic nerve, from cattle and from wild animals "until this day."
The reason: the angel who wrestled Jacob touched and took hold of the hollow of his right thigh, at the place of the sinew that shrank. For thousands of years afterward, Jewish butchers have removed that sinew in memory of the wound.
Why remember a wound with a commandment?
The rabbis puzzled over this. Most commandments commemorate triumphs — the exodus, the giving of Torah, the dedication of the Temple. But this one commemorates an injury. Every Friday night, when a Jewish household sits down to a roast, the meat is missing a particular nerve because a patriarch limped across a river.
One answer: Jewish memory refuses to forget the cost of its own blessings. Israel did not become Israel in a moment of glory. It became Israel in a moment of pain. The missing nerve is a weekly reminder — in the most intimate of spaces, the dinner table — that the covenant was purchased with struggle.
The takeaway: the scars of the patriarchs live in your kitchen, woven into the laws of what you do and do not eat.