Lawful enslavement was restricted to two instances: capture in war (on the condition that the prisoner is not a Muslim), or birth in slavery. [wiki]
Though a free Muslim could not be enslaved,
conversion to Islam by a non-Muslim slave did not require that he or she then should be liberated. Slave status was not affected by conversion to Islam. [Lewis, Bernard (1990).
Race and Slavery in the Middle East. New York: Oxford University Press.p.9]
In theory free-born Muslims could not be enslaved, and the only way that a non-Muslim could be enslaved was being captured in the course of holy war.[Sikainga, Ahmad A. (1996).
Slaves Into Workers: Emancipation and Labor in Colonial Sudan. University of Texas Press.
]
Bukhari: [FONT="]Vol. 5-#512 Narrated Anas: ".....The prophet had their warriors killed, their offspring and woman taken as captives...."
[/FONT][FONT="]Vol. 5-Chapter 67 Narrated Ibn Ishaq: The Ghazwa (attack upon) Uyaina bin
Hisn waged against Banu Al-Anbar, a branch of Banu Tamim. The prophet sent Uyaina to raid them. He raided them and killed some of them and took some others as captives.
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In the Sirat Rasulallah, Muhammad massacred 800 males and took their women and children as slaves. He kept at least one Jewish female named Rayhana as his concubine, and gave the rest away to the Muslims. The Sirat says (p466) "Then the apostle divided the property, wives, and children of Banu Qurayza among the Muslims....[/FONT]
Traditional Islamic law (
fiqh) elaborates significantly on the Quranic material concerning slavery. The enslavement of war captives is regulated, along with the purchase and sale of slaves. While it is not permissible to enslave other Muslims, the jurists clarify that if a non-Muslim converts to Islam after enslavement, he or she remains a slave and may be lawfully purchased and sold like any other slave.
[Islam and Slavery]
"Slavery is a part of Islam. Slavery is part of jihad, and jihad will remain as long there is Islam."
[Al Fawzan Sheik Saleh Al-Fawzan a member of the Senior Council of Clerics, Saudi Arabia's highest religious body]
Let me know if you want more.