"As for the thief, both male and female, cut off their hands. It is the reward of their own deeds, an exemplary punishment from Allah. Allah is Mighty, Wise." - Quran 5:38 (read more)

"Narrated Kurib: the freed slave of Ibn 'Abbas, that Maimuna bint Al-Harith told him that she manumitted a slave-girl without taking the permission of the Prophet. On the day when it was her turn to be with the Prophet, she said, "Do you know, O Allah's Apostle, that I have manumitted my slave-girl?" He said, "Have you really?" She replied in the affirmative. He said, "You would have got more reward if you had given her (i.e. the slave-girl) to one of your maternal uncles." - Sahih Bukhari 3:47:765 (read more)

"...it is not permissible to marry her [an atheist], as she is still a Kafir (non-Muslim) and has not yet embraced Islam wholeheartedly without any doubt. Allah says: "And do not marry Al-Mushrikât (idolatresses, etc.) till they believe (worship Allâh Alone). And indeed a slave woman who believes is better than a (free) Mushrikah (idolatress, etc.), even though she pleases you."(Al-Baqarah 2:221). Being convinced by Islam and wishing to embrace it is not an excuse for you to get married with her..." - Dr. Abdullah Al-faqih