"Prohibited to you (For marriage) are:- Your mothers, daughters, sisters; father's sisters, Mother's sisters; brother's daughters, sister's daughters; foster-mothers (Who gave you suck), foster-sisters; your wives' mothers; your step-daughters under your guardianship, born of your wives to whom ye have gone in,- no prohibition if ye have not gone in;- (Those who have been) wives of your sons proceeding from your loins; and two sisters in wedlock at one and the same time, except for what is past; for Allah is Oft-forgiving, Most Merciful;" - Quran 4:23 (read more)

"So the Quraish and the Ansar became angry and said, "He (i.e. the Prophet, ) gives the chief of Najd and does not give us." The Prophet said, "I give them) so as to attract their hearts (to Islam)." - Sahih Bukhari 4:55:558 (read more)

"The Shafi´ites, Hanbalites and Malikites say: The verdict for the female apostate is the same as for the male. She must be called on to return to Islam for three days, prior to her death, for an evil-doer may have confused her understanding; thus the possibility exists for her being released from her confusion. Offering the apostate a time limit for repentance has been approved." - Abdurrahmani'l-Djaziri