The Master Or Mistress Who Beats Their Servants

While the immorality of and the punishments for acts like murder (Genesis 9:6, Exodus 21:12-14) are not solely about servants/slaves, plenty of Exodus 21 pertains to servitude in particular.  For instance, verses 20-21 say that if a person beats their male or female servants with a rod and they die, they must be punished, but they are not to be punished if the servant can physically function after a day or two.  Though it would not have to specifically say this in order to be contrary to the stereotype that violence against men is acceptable or less evil compared to violence against women, the gender egalitarianism here is obvious.  Also, despite seeming initially to some people to trivialize or even encourage all nonfatal beatings of servants, this passage absolutely does not put forth such a notion, either on its own or in light of other verses in Mosaic Law.

As neglected as it might be by many readers, Exodus 21:20-21 does not prescribe beating one's slaves (whom are not slaves in the sense of the American system of slavery) on a whim or in just any manner someone might subjectively wish to.  It is specifying when to punish a master/mistress for murder if they give their servants corporal punishment with a rod or whip, which is permitted for servants as it is for free men and women as long as it is for an actual, applicable moral offense and it does not exceed 40 strokes (Deuteronomy 25:1-3).  If the slave does not die, but he or she instead recovers from the blows which are only permitted in very specific contexts and with strict boundaries, then the master or mistress cannot be guilty of murder, which is always a capital sin.  This is what Exodus 21:20-21 is about.

If the beating was applied out of malice, in independently unjust ways (such as by involving more than 40 strikes or in combination with some other penalty), or when a person was for unrelated reasons already likely unable to survive such an ordeal, then the person in charge of the servant would face capital punishment for murder if the slave died (Exodus 21:12).  The latter of these three is clarified by Exodus 21:20-21 because these verses teach that if the slave dies as a direct result no matter what would otherwise be legitimate about the corporal punishment, the master or mistress has to be punished.  The other things are already taught directly or by logical extension from the aforementioned laws about murder or the maximum number of lashes.  One would not need the passages about these sins to mention servants since the injustices are broader than slave abuse.

In Exodus 21 itself, verses 26-27 mention shortly after that a servant should go free if they face genuine physical abuse, especially abuse that results in permanent injury.  This is the servant's compensation.  The law about beating focuses strictly on whether corporal punishment (legitimately applied or not) ends a life and how a given punishment is morally required if it does.  Exodus 21 separately addresses how of course a servant does not deserve to be struck unjustly and has no reason to simply endure just any kind of treatment whatsoever (see also Deuteronomy 23:15-16).  Regardless of their remaining debt or if they had otherwise pledged themselves to their masters for life rather than being released by default in the seventh year (Deuteronomy 15:12-17), a slave abused, especially by the infliction of permanent or serious injury, must go free.  Exodus 21:20-21 does not contradict this because it is not about mutilation, but illicit killing by malice or by recklessness.