All Mistreatment Is Abuse

Whatever the moral framework, abuse of a person is mistreating them.  The popular language of "sexual abuse" and "physical abuse" might lead some people to assume that abuse is just a given subcategory of wrongful treatment worse than the rest.  Abuse itself, though, is simply mistreatment.  Sexual abuse would be mistreating someone sexually, physical abuse would be mistreating someone physically, and so on with psychological/emotional or financial abuse.  Ultimately, any form of unjust behavior is abuse of someone or something.  Some are more vicious and blatant, like public and unjust torture, and others can be more easily concealed or overlooked, like private words of illicit contempt.

Not all abuse is equally severe or immoral, but it is all abuse.  Some categories are worse than others and certain potential abuses within each category are worse than others.  As I said, what actually is or is not abuse depends on the tenets of a specific worldview.  If nothing is immoral because all things are amoral, neither good nor evil, then nothing is abusive in a moralistic sense in reality, only according to various particular false philosophies.  However, some actions would still be cruel or exploitative.  The Christian worldview, a heavily moralistic one, acknowledges many things as abusive, including some that modern human rights advocates (who almost always just believe in rights on the basis of subjective conscience or arbitrary and irrelevant social conditioning) likely do not think are evil.

Biblically, it is abuse to intentionally strike or injure someone (Exodus 21:15, 18-19, 22, 26-27) outside of self-defense or justice (Exodus 21:23-25, 22:2-3, Leviticus 20:27, Deuteronomy 25:1-3, etc.), unless the blow is consensual (note the context of quarrelling in Exodus 21:18-19, rather than something like wrestling).  It is abuse to not pay one's workers before sunset the day their shift ends (Leviticus 19:13, Deuteronomy 24:14-15).  It is abuse to either kidnap someone (Exodus 21:16, Deuteronomy 24:7) or to steal mere possessions from them (Exodus 20:15, 22:1, 4, 7-9, Numbers 5:5-7).  It is abuse to make workers labor for seven days in the same week (Exodus 20:8-11, Deuteronomy 5:12-15).  Likewise, it is abuse, in a populated agricultural area, to not leave the edges of fields unharvested so that the poor can freely take from them (Leviticus 19:9-10).  Among other things, it is also abuse to not love by at least fulfilling one's obligations to them (Leviticus 19:18, Romans 13:8-10).  It is not abuse to stone somebody to death if their actions truly deserve it (Deuteronomy 13:6-10, 17:2-7, and so on), but to inflict greater and artificially prolonged suffering on someone who deserves death by stoning could only be abusive.

There is no single category of abuse (or, amorally, cruel/exploitative treatment), and this is by no means an exhaustive summary of the human rights (in select cases, the rights of all humans that are workers, parents, and so on) taught by the Bible.  For instance, there is also the right for spouses to not be sexually neglected (Exodus 21:10-11, 1 Corinthians 7:2-5), the right to not be made to serve as a soldier against one's will (Deuteronomy 20:5-9), the right to only be legally punished on the testimony of at least two or three witnesses (Deuteronomy 19:15), the right to not wear clothing (Genesis 2:25, Exodus 22:26-27, Deuteronomy 4:2), and the right for servants to be released after seven years with a generous severance arrangement (Deuteronomy 15:12-14).  Any sort of deviance from what is prescribed is abuse on Christian philosophy, no matter how much alleged Christians since the time of Christ have denied the ongoing nature of these obligations.

Now, some rights would necessarily exist if Christianity is true even if they are not explicitly mentioned in Yahweh's moral revelation.  That is, while no one can know what Biblical human rights there are from conscience or hearsay or preference or cultural norms (from nothing apart from reading the Bible while making no assumptions), the text does not have to list literally all of them for its worldview to entail them.  Exodus 21:26-27 says a male or female slave who is abused so that their eye is destroyed or their tooth is knocked out must go free.  The text gives examples of two particular physical abuses that are clearly subsets of a greater category that is condemned as a whole.  It does not mention other body parts, but it does not need to.  The same right to emancipation would also apply in other such cases of abuse.  Conceptual consistency and logical necessity reveal what rights follow from others or what scope a particular moral right has.  Whatever the right, though, to mistreat the person by not acting in accordance with their right is to deviate from one's obligations towards them, and this is abuse in every single instance.