He that striketh his bondman or bondwoman with a rod, and they die under his hands, shall be guilty of the crime.
 But if the party remain alive a day or two, he shall not be subject to the punishment, because it is his money.
Essentially the passage is telling us that rather than the punishment for the slave owner to be death, the death of his slave is his punishment because A) the slave works for him and to lose a worker is to lose production and B) Since he paid for the slave he is also losing his investment in the slave and the money he paid for his services.
The reason this passage is different than Exodus ch 21 v 20 (He that striketh his bondman or bondwoman with a rod, and they die under his hands, shall be guilty of the crime.
To be guilty of the crime is to be punished, usually by the sword. A death penalty) is because if the slave dies days after it is supposed that the owner didn't intend to kill the slave- besides, if he did it is his
loss as a business man.
But Kayla I think more than anything you're looking for a justification as to why it would be ok to have slaves in the first place and why our Almighty and Loving Father would permit it. I will address this point.
Firstly, in looking to discredit the Bible people don't pay much attention to it. Thats because if you take the time to understand it as the word of God
you can easily deduce that there is nothing
wrong with it. It is the truth.
The person who told you this is outdated is working on a false assumption that regulating a behavior is the same as approving the behavior. This is false. We need look no further than any
system of law. Our own will do just fine. Murder is illegal. However, in the course of ones actions attributing to the death of innocence we see that it is prosecuted differently with different punishments. Murders that are planned and organized with the absolute end goal to end a life usually carry a 1st degree murder charge. Typically that sentence is life in prison or execution. Then we have second degree murder which is usually a homicide in the course of a felony- like if you were stealing and someone caught you and you killed them. Then there is third degree murder which is basically not intending to, but killing a person through an assault. Second and third degree murders have different punishments than first degree murder.
Then after that we have all sorts of other things to sort out. Like insanity. If the person was insane its likely they won't be charged as harshly if they were deemed competent. And then there's also manslaughter. A million and one ways that a person can committ a crime and a million and one ways they can be punished for it depending on the course of action that led up to the crime.
So to put it simply laws have always, still do, and will continue to exist as a protocol of justice when evil is done. They do not
necessarily exist as an approval but a regulation of actions. Exodus is no exception to this.
Funny thing is, nothing of the above actually matters because the bigger assumption that a person is making here is that the slavery depicted in these laws is involuntary servitude. It is not. First, examine Exodus chapter 21 verse 16:He that shall steal a man, and sell him, being convicted of guilt, shall be put to death.
Obviously slave trade was illegal and punishable by death. The slavery referred to in the bible is not the slavery we know about in the 17 and 18 hundreds. Western slavery was a way for the rich to benefit without having to work and by the toils and sweat of a kidnap victim. It is, in fact, in that respect one of the sins against the Holy Ghost: defrauding laborers of their wages.
slavery in bible days in fact benefited the poor. It was a way to escape poverty. Families would actually sell their children. We would look at this now and be aghast but the truth of it is that it was like giving a child away for adoption. It was giving the child a better life. Slavery contracts often stipulated work in exchange for personal protection and economic advance. People would "sell themselves" to be bondsmen or bondswomen so that they might have a place to eat and to sleep and a way of making a living. The relationship of a "slave" and his "master" was most usually initiated by the slave.
Bible "slaves" are akin to modern day independent contractors.
Most "complaints" against the bible are based on a false assumption that something means something that it doesn't. Places like religioustolerance.com LOVE to quote the bible and expose its evil secrets but time and time again it is shown to us through scripture itself and the grace of God that these are false and ultimately ignorant claims that that aim to "discredit" God like a child who gives a teacher the middle finger under his desk.
I hope this helped. Feel free to copy and paste the important parts of this text and give them to your friend if you'd like.