"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 Al-Bara bin Azib: Allah's Apostle sent a group of persons to Abu Rafi. Abdullah bin Atik entered his house at night, while he was sleeping, and killed him." - Sahih Bukhari 5:59:370 (read more)

"Allah says: "There is no compulsion in religion"...But, this verse is abrogated by the verse of "fighting...Therefore, all people of the world should be called to Islam. If anyone of them refuses to do so, or refuses to pay the Jizya they should be fought till they are killed. This is the meaning of compulsion. In the Sahih, the Prophet said: "Allah wonders at those people who will enter Paradise in chains", meaning prisoners brought in chains to the Islamic state, then they embrace Islam..." - Ibn Kathir