Mishnayos Chullin Perek 7 Mishnah 6

The prohibition of eating the sciatic nerve applies to a kosher animal and does not apply to a non-kosher animal. Rabbi Yehuda says: It applies even to a non-kosher animal. Rabbi Yehuda said in explanation: Wasn’t the sciatic nerve forbidden for the children of Jacob, as it is written: “Therefore the children of Israel eat not the sciatic nerve” (Genesis 32:33), yet the meat of a non-kosher animal was still permitted to them? Since the sciatic nerve of non-kosher animals became forbidden at that time, it remains forbidden now. The Rabbis said to Rabbi Yehuda: The prohibition was stated in Sinai, but it was written in its place, in the battle of Jacob and the angel despite the fact that the prohibition did not take effect then.