Exodus 21:20, 26-27

And if a man smite his servant, or his maid, with a rod, and he die under his hand; he shall be surely punished.

And if a man smite the eye of his servant, or the eye of his maid, that it perish; he shall let him go free for his eye's sake. And if he smite out his manservant's tooth, or his maidservant's tooth; he shall let him go free for his tooth's sake.