Sunan at-Tirmithiy كتاب الرضاع
The Messenger of God, peace and blessings of God be upon him, said, "Indeed, God forbade by breastfeeding (1) what is forbidden by kinship (2) (with regards to marriage)." Footnotes: 1. A woman becomes a child's breastfeeding mother only if she nurses that child five times during its first two years of life and thus becomes forbidden to him in marriage. 2. Specified in the verse: “Prohibited to you [for marriage] are your mothers, your daughters, your sisters, your father's sisters, your mother's sisters, your brother's daughters, your sister's daughters, your [milk] mothers who nursed you, your sisters through nursing, your wives' mothers, and your step-daughters under your guardianship [born] of your wives unto whom you have gone in. But if you have not gone in unto them, there is no sin upon you. And [also prohibited are] the wives of your sons who are from your [own] loins, and that you take [in marriage] two sisters simultaneously, except for what has already occurred. Indeed, Allah is ever Forgiving and Merciful.” an-Nisā' 4:23 Click on ḥadīth to read more
Ibn-'Abbās was asked about a man who had two bondswomen, one having breastfed a little girl and the other one a little boy, if it was permissible (as defined by God) for the boy to marry the girl. "No," he replied, "the seminal fluid (1) is the same." (2) Footnotes: (1) which caused the women's pregnancies and their consequent ability to lactate. (2) This is the view held by Aḥmad and Isḥāq. Click on ḥadīth to read more
I married a woman. A black woman then came to us and claimed, "I have definitely breastfed the two of you." So I went to the Prophet, peace and blessings of God be upon him, and told him, "I married this woman, daughter of this man, then a black woman came to us and claimed that she had breastfed the two of us, but she is a liar." So he turned away from me. I moved to face him, but again he averted his face. I reiterated, "She is certainly a liar!" He replied, "How can you be intimate with her (i.e. your wife) when this woman is convinced that she breastfed you both? Let her go. (1)" Footnotes: (1): i.e. separate from your wife. Click on ḥadīth to read more
Barīrah's husband was a bondsman [at the time she was freed], so the Messenger of God, peace and blessings of God be upon him, gave her the choice [to either remain with him or be separated]. She opted to be single. Had he been a free man, he would not have given her that choice. (1) Footnotes: (1): This last sentence was not said by 'Ā'ishah, but rather by 'Urwah, one of the narrators in the chain of transmission. Click on ḥadīth to read more
The Prophet, peace and blessings of God be upon him, saw a woman, so he went to Zaynab (his wife) and fulfilled his need (for intimacy). He then came out and said, “When a woman approaches, she does so in a devilish way (stirring temptations). So if anyone of you sees a woman and likes her, he should go to his wife and satisfy his need, for indeed she has what that woman has.” Click on ḥadīth to read more