Exodus 21:20-21

"And if a man smite his servant, or his maid, with a rod, and he die under his hand; he shall surely be punished. Notwithstanding, if he continue a day or two, he shall not be punished, for he is his money."

This was a protective right granted to slaves that they should not be beaten to death! If that seems like a small blessing to us, let it be remembered that under the system in vogue all over the pagan world of that era, and extending down even until apostolic times, the Roman Law, in force all over the world, provided as a penalty against slaves, even for trivial and unintentional violations, that shame of the whole pagan world "flagellis ad mortera" (beaten to death),[21] a penalty usually inflicted in the presence of all the other slaves of a master. God here provided that punishment should be meted out to a slave-owner for following that pagan custom. Also, in case of the dismemberment of a slave, his instant freedom from slavery was automatically provided (Exodus 21:26,27). Also, there was a protective right established here for the slave-owner who was not to be charged with murder in case a slave died under the lash, but he was to be punished.

If the slave, suffering such a punishment, survived even a few days and then died, the master was held free of the penalty of punishment, the loss of his slave being accounted a sufficient penalty.

"For he is his money ..." "The loss of the slave, under the circumstances, was accounted as a punishment.[22]