"...If the party liable is mentally deficient, or weak, or unable Himself to dictate, Let his guardian dictate faithfully, and get two witnesses, out of your own men, and if there are not two men, then a man and two women, such as ye choose, for witnesses, so that if one of them errs, the other can remind her. The witnesses should not refuse when they are called on (For evidence)." - Quran 2:282 (read more)

"Narrated by Gaber bin Abdullah: We were with the messenger of Allah, PBUH and he asked for a drink. One of his men said: "Oh Messenger of Allah, Can we offer you wine to drink?" He said Yes. He (Gaber) went out looking for the drink and came back with a cup of wine. The messenger (PBUH) asked:”Have you fermented it, even with one piece of ferment?” He (Gaber) said "yes" and he (Muhammad) drank." - Sahih Muslim 3753 (read more)

"The Zanj [blacks] are so uncivilized that they have no notion of a natural death. If a man dies a natural death, they think he was poisoned. Every death is suspicious with them, if a man has not been killed by a weapon." - Abu Rayhan al-Biruni