Cross reference
Genesis 32:32
32 For this reason the children of Israel, even today, never take that muscle in the hollow of the leg as food, because the hollow of Jacob's leg was touched.
1 Samuel 5:5
5 So to this day no priest of Dagon, or any who come into Dagon's house, will put his foot on the doorstep of the house of Dagon in Ashdod.