"The Quran contains a number of verses aimed at regulating slavery and mitigating its negative impact. It calls for the manumission (freeing) of slaves. It prescribes kindness towards slaves. Slaves are considered morally equal to free persons, however, they have a lower legal standing. All Quranic rules on slaves are emancipatory in that they improve the rights of slaves compared to what was already practiced in the 7th century. Many Muslims have interpreted Quran as gradually phasing out slavery.
The Quran calls for the freeing of slaves, either the owner manumitting the slave, or a third party purchasing and freeing the slave. The freeing of slaves is encouraged is an act of benevolence, and expiation of sins. Quran 24:33 devises a manumission contract in which slaves buy their freedom in installments. Two other verses encourage believers to help slaves pay for such contracts. According to Maurice Middleberg, "Sura 90 in the Quran states that the righteous path involves 'the freeing of slaves.'" One of the uses of zakat, a pillar of Islam, is to pay for the freeing of slaves.
The Quran prescribes kind treatment of slaves. Quran 4:36 calls for good treatment to slaves. The Quran recognizes the humanity of slaves, by calling them "believers", recognizing their desire to be free, and recognizing female slaves' aversion to prostitution. Several verses list slaves as members of the household, sometimes alongside wives, children and other relatives.
The Quran recognizes slaves as morally and spiritually equal to free people. God promises an eternal life in the Hereafter. This equality is indicated in Quran 4:25, which addresses free people and slaves as “the one of you is as the other” (ba'dukum min ba'din). Quran 39:95 refers to master and slave with the same word. However, slaves are not accorded the same legal standing as the free. Slaves are considered as minors for whom the owner is responsible. The punishment for crimes committed by slaves is half the punishment as to be meted out on free persons. The legal distinction between slaves and the free is regarded as the divinely established order of things, which is seen as part of God's grace.
The Quran recognizes slavery as a source of injustice, as it places the freeing of slaves on the same level as feeding the poor. Nevertheless, the Quran doesn't abolish slavery. One reason given is that slavery was a major part of the 7th century socioeconomic system, and it abolishing it would not have been practical. Most interpretations of the Quran agree that the Quran envisions an ideal society as one in which slavery no longer exists.
Slaves are mentioned in at least twenty-nine verses of the Quran, most of these are Medinan and refer to the legal status of slaves. The legal material on slavery in the Quran is largely restricted to manumission and sexual relations. The Quran permits owners to take slaves as concubines, though it promotes abstinence as the better choice. It strictly prohibits slave prostitution. According to Sikainga, the Quranic references to slavery as mainly contain "broad and general propositions of an ethical nature rather than specific legal formulations." The word 'abd' (slave) is rarely used, being more commonly replaced by some periphrasis such as ma malakat aymanukum ("that which your right hands own"). However the meaning and translation of this term has been disputed. Ghulam Ahmed Pervez argued that the term is used in the past-tense in the Quran, thus signalling only those individuals who were already enslaved at the dawn of Islam. This slight change in tense is significant, as it allowed Parvez to argue that slavery was never compatible with the commandments of the Quran and is in fact outlawed by Quranic Law.
There are many common features between the institution of slavery in the Quran and that of neighboring cultures. However, the Quranic institution had some unique new features. Bernard Lewis states that the Quranic legislation brought two major changes to ancient slavery which were to have far-reaching effects: presumption of freedom, and the ban on the enslavement of free persons except in strictly defined circumstances. According to Brockopp, the idea of using alms for the manumission of slaves appears to be unique to the Quran, assuming the traditional interpretation of verses. Similarly, the practice of freeing slaves in atonement for certain sins appears to be introduced by the Quran (but compare Exodus 21:26-7). The forced prostitution of female slaves, a long practiced custom in the Near Eastern, is condemned in the Quran. Murray Gordon notes that this ban is "of no small significance." Brockopp writes: "Other cultures limit a master's right to harm a slave but few exhort masters to treat their slaves kindly, and the placement of slaves in the same category as other weak members of society who deserve protection is unknown outside the Quran. The unique contribution of the Quran, then, is to be found in its emphasis on the place of slaves in society and society's responsibility toward the slave, perhaps the most progressive legislation on slavery in its time.""