"Such of your women as have passed the age of monthly courses, for them the prescribed period, if ye have any doubts, is three months, and for those who have no courses (it is the same): for those who carry (life within their wombs), their period is until they deliver their burdens: and for those who fear Allah, He will make their path easy." - Quran 65:4 (read more)

"Narrated Qatada: Anas bin Malik said, "The Prophet used to visit all his wives in a round, during the day and night and they were eleven in number." I asked Anas, "Had the Prophet the strength for it?" Anas replied, "We used to say that the Prophet was given the strength of thirty (men)." And Sa'id said on the authority of Qatada that Anas had told him about nine wives only (not eleven)." - Sahih Bukhari 1:5:268 (read more)

"The Jews and early Christians were suspected of altering the text of the Taurat and Injil; but in the opinion of eminent doctors and theologians it was not practicable thus to corrupt the text, because those Scriptures were generally known and widely circulated, having been handed down from generation to generation." - Fakhruddin Razi