18 “If men quarrel and one strikes the other with a stone, or with his fist, and he doesn’t die, but is confined to bed; 19 if he rises again and walks around with his staff, then he who struck him shall be cleared; only he shall pay for the loss of his time, and shall provide for his healing until he is thoroughly healed. 20 “If a man strikes his servant or his maid with a rod, and he dies under his hand, the man shall surely be punished. 21 Notwithstanding, if his servant gets up after a day or two, he shall not be punished, for the servant is his property. Exodus 21:18-21WEB
This passage contains a series of statutes, directed toward Israel, prescribing proper penalty for an assault where the victim is incapacitated, but not killed. There are two scenarios:
Verse 19 gives the general rule: if a man is attacked and incapacitated for any period of time, the attacker shall pay for the loss of time and pay for all of his related medical expenses until he is fully healed.
Verse 21 gives an exception: if the man who was attacked was the servant of the attacker, then the attacker is not punished, because the servant is his property.
Verse 20 qualifies the exception: if the servant is killed, the master shall be punished accordingly.
This passage is part of the Civil/Judicial Law.
This law fits in with other laws related to Human Judicial Response.
These commands are understood to represent an abiding obligation for modern governments.
Notes on Interpretation/Application
"Because the slave is his property"
The maximum term for Israelite slavery ends at the year of Jubilee (Per Deut 15:12). For this reason, the value of a slave is calculated from the point of sale until the year of Jubilee (Leviticus 25:50-52). This date of release is not adjusted for slaves who were injured during their service; whether on or off the job.
This means, if a master strikes his slave and incapacitates the slave, then the time during which the slave is incapacitated is lost income for the master. If the master had to make additional payment for the slave's time, it would be a redundant penalty.
As additional support for this interpretation, the Hebrew word which is here translated "property" is literally translated "silver", prompting some translations to render this, "because the slave is his money". The implication here is that an injured slave is already "lost money" for the master.