This is in reference to your Fatwa: 90298, where you have mentioned that Mariya Al-Qibtiyyah was not Prophet Muhammad’s wife but his slave-girl and he used to have sexual intercourse with her. I am confused about this. I have read in many places that the Prophet married Mariya and also had a son from her named Ibrahim. If the Prophet did not marry her then how can he have sexual intercourse with her, which will be considered Haraam?
Please clarify.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

You quoted correctly what we mentioned in the Fatwa, that Maariyah Al-Qibtiyyah was not one of the Prophet's, sallallaahu ‘alayhi wa sallam, wives. Yet, he used to have sexual intercourse with her as an owned female slave and she gave birth to his son Ibraaheem.

As for wondering how the Prophet, sallallaahu ‘alayhi wa sallam,  could have had sexual intercourse with her without marrying her, then the answer is that Allaah The Almighty permitted a man to have sexual intercourse in two cases: 1) With his wife. 2) With a female slave that one owns.

Therefore, it is permissible for a man to have a sexual intercourse with his wife, and also with a female slave he possesses in his right hand. Allaah The Almighty Says (what means): {And those who guard their chastity (i.e. private parts, from illegal sexual acts). Except from their wives or (the captives and slaves) that their right hands possess, for then, they are free from blame.} [Quran, 23:5-6]. So a man is not blamed for having sexual intercourse with his female slave that his right hand possesses. Maariyah Al-Qibtiyyah was a female slave owned by the Prophet, sallallaahu ‘alayhi wa sallam, and she was given to him as a present by the king of Egypt.

To conclude, having sexual intercourse with a female slave that one possesses is not forbidden as the questioner thought, and the Prophet, sallallaahu ‘alayhi wa sallam, is the furthest person from what is illegal and unlawful.

Allaah Knows best.