@faithinhim, you are conflating two very separate things - whether a woman is a man's sexual partner (wife / concubine), and whether she is a slave. These are completely independent.
These scriptures and there are also others, demonstrate that there is a difference between a woman who is a slave which is a concubine and a woman who is free which is a wife.
You are ignoring the cases of a slave who is NOT a concubine, and a free woman who is NOT a wife. You are assuming all slaves are concubines, and all free women are wives, and that is making the whole thing confusing to you when it really is quite simple.
Are you suggesting that a concubine is also a wife that can be passed around by her master to another slave.
Of course not. Exodus 21:2-4 is describing the case of a man who owns many slaves, both men and women, most of whom are not his personal concubines. And he gives one of his female slaves (not his own concubine, just the slave he bought to milk the goats) to one of his male slaves to be that slave's wife. Ignoring the whole slavery issue (a large can of worms), and just thinking about the issue of sexual partnership - this woman is only ever the sexual partner of one man. She is only ever the wife / concubine / whatever term you prefer of one man - the male slave.
But she still has a fixed-term-contract job - she is the woman who milks the goats, she's bound to keep doing that job (in slavery terms, she is the financial property of the master, he owns her labour). So the male slave can't just leave and take her away from her employment. He has the choice between leaving himself with her remaining at her job, or them both remaining in the employment of their master.
The relationship between master and slavewoman in this case is simply a financial matter. She is never described as the master's concubine, or wife, nor is the slightest hint given that she has a sexual relationship with him. It has nothing to do with sex, I do not know why you have got the idea that this woman is a concubine. She is clearly described as the wife of a male slave, not the concubine of her master.
The differences between a woman who is free and a woman who is a slave are stark and cannot be ignored. How would you explain these differences in God's law?
The very passage you have quoted actually contradicts your point. Exodus 21:4, states "If his master gives him a wife". Why is this woman called a "wife"? Surely if all slaves are concubines, this would say "if his master have given him a concubine". Is this slavewoman truly a wife, or is she not a slavewoman? Or is there not as clear a difference as you were assuming?
