Only a few servants of Job's escape the destruction that befalls his flocks and children to tell him what has happened to various animals, family members, and other servants. A significant number of his servants are among the blessings God allows Satan to take from him (Job 1:15-17); the remaining male and female servants are estranged from him (19:15-16). As his "friends" assume that he must have done something evil (even if an idea is true, assumptions are always epistemologically invalid), or else God would not have caused or allowed any of this, Job defends himself by listing miscellaneous sins he has not committed or has taken great care to avoid. While a figure in a narrative saying something is good or evil does not mean that the notion in question is morally correct by Biblical standards, as something in the text must specify that God approves of or condemns something to establish this, what Job says about his treatment of his servants is in perfect alignment with the plain moral teachings of Genesis, Exodus, and Deuteronomy in particular.
Job 31:13-15--"'If I have denied justice to any of my servants, whether male or female, when they had a grievance against me, what will I do when God confronts me? What will I answer when called to account? Did not he who made me in the womb make them? Did not the same one form us both within our mothers?"
From statements like this, it is impossible to in any way derive knowledge of what constitutes Biblically just treatment of servants or anyone else, except that of course the same treatment is just for men and women in equivalent situations, as anything else is inconsistent with Genesis 1:26-27 and 5:1-2, and more importantly, with reason. This much is required by logic since the same actions committed by or against men and women could only be equally good or evil; women and men are both people, neither having more value or rights than the other if such a thing as moral value and rights exists, contrary to various misandrist and misogynistic worldviews. Because these are logically necessary truths, although there is no logical necessity in the actual existence of good and evil, the Bible would have to be consistent with them for its moral philosophy to even be logically possible. Clarifying more of the particulars of how servants should and should not be treated, the following passages also specifically mention male and female servants, and they are not all of the verses in Mosaic Law on the ethics of behavior towards servants:
Exodus 20:8-10--"Remember the Sabbath day by keeping it holy. Six days you shall labor and do all your work, but the seventh day is a sabbath to the Lord your God. On it you shall not do any work, neither you, nor your son or daughter, nor your male or female servant, nor your animals, nor any foreigner residing in your towns."
Exodus 21:20--"Anyone who beats their male or female slave with a rod must be punished if the slave dies as a direct result,"
Exodus 21:26-27--"An owner who hits a male or female slave in the eye and destroys it must let the slave go free to compensate for the eye. And an owner who knocks out the tooth of a male or female slave must let the slave go free to compensate for the tooth."
Deuteronomy 15:12-13--"If any of your people--Hebrew men or women--sell themselves to you and serve you six years, you must let them go free. And when you send them away, do not send them away empty-handed."
Since some idiots think that because the Bible speaks (due to the context of getting a wife) of a male slave going free in Exodus 21:2, a female slave would not also go free after six years of service, Deuteronomy 15:12 is a blatant reminder in this very specific case that never are there prescribed gender-specific obligations (Genesis 1:26-27) that are not about literal anatomy (such as Leviticus 19:27's condemnation, in context pertaining to pagan expression, of cutting beards), as opposed to psychological stereotypes. Just because a man was specifically in view in Exodus 21:2--in this instance given the subsequent verses, it is not that a male word is used for someone already directly or by extension confirmed to be of either gender as with older translations of Exodus 21:26-27, Leviticus 13:29-39, Deuteronomy 17:2-7, and so on--does not mean a woman does not have the same right, and vice versa as applicable! This does not follow logically. For yet another passage affirming utter gender equality in the release of servants despite the male wording of Exodus 21:2, see Jeremiah 34:8-17, where God promises to destroy people who refused to fully release male and female servants of their own countrypeople after six years of labor.
As for the book of Job, what it says about slaves is consistent with all of this. Whether because of sheer rationality, precise moral revelation from Yahweh, or both, Job does not pretend like his servants are only useful instruments to hurt or discard as he pleases, as opposed to full persons, nor does he pretend that men and women are not equal. It would be extremely unjust even according to the very explicit wording of verses from Exodus to, for instance, think that the Sabbath rest is only for male servants or that only female servants deserve protection from physical abuse, and Job does not think such things. He recognizes that all of his servants, both men and women, are not subhuman because of their social status or gender and that the same God brought them into being. In Job 31:13-15, as shown, he fully and rightfully expects to be confronted by God if he was to disregard his slaves or for mistreating ether men or women.
Of course, it would also be inconsistent for Biblical ethics to hold that treatment of male and female slaves must be equal, but not for men and women who become free or who never were slaves. If killing a slave of either gender by abusive corporal punishment as is emphasized by the direct wording of Exodus 21:20, which mentions male and female slaves, then of course the commands of Exodus 21:12-14 would apply no matter the gender of the perpetrator or victim of general murder. This is in spite of the default male wording of Exodus 21:12-14, though the Hebrew and English words "man", "he", and so on can refer to both male and female people. For this flexibility of male nouns and pronouns alone, a Bible verse mentioning men is applicable to both genders unless something in it or its context specifies otherwise, and vice versa whenever women and men can commit the same actions that are good or evil in themselves, not because of someone's genitalia. Logical equivalence of actions by or against men and women would necessarily dictate that this is what would be true of any text's moral system unless the contrary is actually stated, in which case the proposed moral framework would contradict logical necessity and thus be incapable of being true.
Now, the gender equality of Genesis 1:26-27 and 5:1-2 also already refutes misogynistic or misandrist interpretations of passages like Exodus 21:12-19 due to default male language, and this is also aside from how the original manuscripts of the Torah sometimes explicitly mention men and women right before or after using male words in summary (Exodus 21:20 tends to do this in older English translations as well, along with many other verses, most of which deal with direct moral commands from God or other matters of moral significance rather than merely descriptive narrative accounts [1]). People who think that retreating behind the sometimes specific male or female language in given parts of Mosaic Law, unless the context requires that a moral doctrine literally just apply to men or to women for anatomical reasons, are fools. See the example of such a thing concerning the circumcision prescription of Leviticus 12:1-3 for males, as well as how 12:6-8 says that a woman who gave birth was the one to make a purification offering; her husband could go with her, but he did not give birth. This does not mean, for instance, that Deuteronomy 25:11-12 would only apply specifically to women commiting sexual assault against men by grabbing their genitalia, as opposed to the other way around or to people of the same gender doing this to each other if those things were to happen. The Bible plainly teaches inside and outside of Mosaic Law that men and women have the same rights and obligations except where their anatomy itself, not fallacious stereotypes about their gender, is in view.
Logic, people. It is very fucking helpful.
[1]. For numerous examples of this in the Torah, most often about the moral status/obligations that all people from all eras have, see Genesis 1:26-27 (KJV, NKJV), 5:1-2 (KJV, NKJV); Exodus 21:20-21 (KJV, NKJV), 26-27 (KJV, NKJV), 22:22-24 (NASB), 35:21-22 (KJV, NKJV); Leviticus 13:29-39 (KJV, NKJV), 25:44-46 (KJV); Numbers 5:5-7 (KJV, NKJV), 6:1-21 (KJV, NKJV); Deuteronomy 13:6-10 (KJV, NKJV), 15:12-18 (KJV, NKJV), 17:2-7 (KJV, NKJV), and 29:14-21 (KJV, NKJV). For examples in other books of the Bible, see the likes of Job 31:13-15 (KJV), Isaiah 24:1-6 (KJV, NKJV), Jeremiah 34:8-17 (KJV, NKJV), Ezekiel 9:4-6 (KJV, NKJV), and 14:12-22 (KJV, NKJV, NIV), two of which were referenced in this post.