Female slaves are the natural by-product of the system of slavery. The situation that prevailed in all societies where the institution of slavery existed was such that slave women were used at will and were employed to gain economic advantage by inciting them towards prostitution. As for Islam, it provided for a facility which would, in the course of one generation, bring an end to the system through the slave women themselves.
The slave woman is the property of the master. However, the master has no right, whatsoever, to incite her towards adultery. Like the male slaves, the female slaves, too, have rights of their own. It is the duty of the master to provide her with food, shelter, clothes and other necessities. Moreover, the Qur'an has asked the owner to make the necessary arrangements for her marriage as well (Qur'an 24:32).
This, in effect, means that the Qur'an has prompted the owner towards having sexual relations with an unmarried female slave. This permission is however restricted to the owner alone. No one else is allowed to use her in this fashion even if it be with the permission of the master!
In giving birth to the child of the master, the slave woman becomes entitled to new rights. Thenceforth, the master has no right to sell her. She becomes the mother of her master's children. These children, too, become entitled to all the rights and privileges enjoyed by the master's other children. Islam disagrees with the Jewish stand that the children born through a slave woman have none of the rights that should naturally be given to them by virtue of paternity. These children are, in all respects, his own children. There is to be no discrimination of any kind between them and the other children. With the death of the master, the slave woman, who is the mother of his children, becomes a free woman. She is then protected by her own children. They, too, like the other children, will becomes entitled to a share in their father's inheritance.
The permission to accept slave women as one's life-partner was, in fact, a provision which would, in the course of one generation, cut out the very root of slavery. In reality, therefore, the permission granted for having relations with slave women was one among the many unique steps taken by Islam in practically eradicating slavery.
It is not possible to equate the permission given for having relations with slave women to adultery. These acts stand at two extreme poles. One is the case of the woman who lives under her master enjoying the protection that he confers upon her. It is a relationship in which he fully agrees to take up the responsibilities that may result as a product of that relationship. It is a relationship in which her personality, beyond the contours defined by sex, is accorded full recognition. It is a relationship which opens to her the door to freedom. As for the second, it is nothing but a carnal relationship with a prostitute without any sort of commitment. The position of the prostitute is, in fact, much worse than that of the slave woman. For, she is nothing more than a soul less animal. Her function is restricted solely to the gratification of the animal passions of man. There is not even a grain of love and compassion in that relationship, not the slightest touch of personal fulfillment even. It is but a transaction made solely for money. Flesh trade! The man who comes for the satisfaction of carnel of his desire is never prepared to take up the responsibility that may accrue from it. He has no obligation towards her. She is only an animal destined to satisfy his sexul appetite. Each one of her relationships will serve only to immerse her even deeper into the mire that is the inhumanity of prostitution. Even the very dream of freedom is alien to her. She is one doomed to embrace the loneliness of orphanhood when in a diseased state, with her skin wrinkled and faded, she ends up being the object of nobody's concern.
What, then, of the tradition which lays open, before the slave, the very door to freedom? And what of the rottings system which drives the woman from one dependence to the other? Any comparison, whatsoever, between these two is impossible because they stand at two opposing and extreme poles. One recognized by benign humanism, the other which leads to depredation and frustration.