Albert Barnes Commentary 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." — Exodus 21:20-21 (ASV)

The Jewish authorities appear to be right in referring this law, like those in Exodus 21:26-27 and Exodus 21:32, to foreign slaves . The protection provided here for the life of a slave may seem to us only a slight one; but it is the earliest trace of such protection in legislation, and it stands in strong and favorable contrast with the old laws of Greece, Rome, and other nations. If the slave survived the severe punishment a day or two, the master did not become liable under the law, because the loss of the slave was considered, under the circumstances, a punishment.