"Glory to Allah, Who created in pairs all things that the earth produces, as well as their own (human) kind and (other) things of which they have no knowledge." - Quran 36:36 (read more)

"Narrated Kurib: the freed slave of Ibn 'Abbas, that Maimuna bint Al-Harith told him that she manumitted a slave-girl without taking the permission of the Prophet. On the day when it was her turn to be with the Prophet, she said, "Do you know, O Allah's Apostle, that I have manumitted my slave-girl?" He said, "Have you really?" She replied in the affirmative. He said, "You would have got more reward if you had given her (i.e. the slave-girl) to one of your maternal uncles." - Sahih Bukhari 3:47:765 (read more)

"The people of Iraq ... do not come out with something between blonde, buff and blanched coloring, such as the infants dropped from the wombs of the women of the Slavs and others of similar light complexion; nor are they overdone in the womb until they are burned, so that the child comes out something between black, murky, malodorous, stinking, and crinkly-haired, with uneven limbs, deficient minds, and depraved passions, such as the Zanj, the Somali, and other blacks who resemble them." - Ibn al-Faqih