If anyone injures his neighbor, whatever he has done must be done to him:

Exodus 21:23
But if a serious injury results, then you must require a life for a life--

Leviticus 24:18
Whoever kills an animal must make restitution--life for life.

Leviticus 24:20
fracture for fracture, eye for eye, tooth for tooth. Just as he injured the other person, the same must be inflicted on him.

Judges 1:7
Then Adoni-bezek said, "Seventy kings with their thumbs and big toes cut off have gathered the scraps under my table. As I have done to them, so God has repaid me." And they brought him to Jerusalem, where he died.

And if a man cause a blemish in his neighbor; as he has done, so shall it be done to him;