"Also (forbidden are) women already married, except those whom your right hands possess. Thus has Allah ordained for you. All others are lawful, provided you seek them from your property, desiring chastity, not fornication. So with those among them whom you have enjoyed, give them their required due, but if you agree mutually after the requirement (has been determined), there is no sin on you. Surely, Allah is Ever All-Knowing, All-Wise." - Quran 4:24 (read more)

"Narrated Anas bin Malik: While we were sitting with the Prophet in the mosque, a man came riding on a camel. He made his camel kneel down in the mosque, tied its foreleg and then said: "Who amongst you is Muhammad?" At that time the Prophet was sitting amongst us (his companions) leaning on his arm. We replied, "This white man reclining on his arm." They then addressed him" - Sahih Bukhari 1:3:63 (read more)

"Mohammed had many male and female slaves. He used to buy and sell them, but he purchased more slaves than he sold, especially after God empowered him by His message, as well as after his immigration from Mecca. He once sold one black slave for two. His name was Jacob al-Mudbir. His purchases of slaves were more than he sold. He was used to renting out and hiring many slaves, but he hired more slaves than he rented out." - Ibn Qayyim al-Jawziyya