Daaim ul Islam devotes an entire chapter to “‘itq”-the freeing of slaves. Slavery was an integral part of warfare: enemies who were not killed in battle were enslaved to ensure that they remained under control. However the freeing of slaves was encouraged by Islam. The Quran mentions not once, but several times, the sawaab of freeing a slave. RasulullahSA elucidates the reward of he who frees a Muslim slave: for each part of the slave’s body, each part of the person who grants him freedom will be protected from hellfire. Amir ul MumineenSA set the ultimate example: in his lifetime, he set free a thousand slaves from his personal wealth which he had accumulated through farming.
Islam has laid down a set of laws for the freedom of slaves: for example a mukatab is a slave who is required to accumulate a given sum for his freedom, while a mudabbar is he who will gain freedom at his owner’s death. Further, a slave girl who bears a child is free after her owner’s death, as is the child. The shariat has also made the freeing of slaves obligatory as part of certain kinds of kaffarat. For example, if a mumin kills another unintentionally, then freeing a slave would be kaffarat for his sin.