Sahih Bukhari Volume 1, Book 3, Hadith 88

حَدَّثَنَا مُحَمَّدُ بْنُ مُقَاتِلٍ أَبُو الْحَسَنِ، قَالَ أَخْبَرَنَا عَبْدُ اللَّهِ، قَالَ أَخْبَرَنَا عُمَرُ بْنُ سَعِيدِ بْنِ أَبِي حُسَيْنٍ، قَالَ حَدَّثَنِي عَبْدُ اللَّهِ بْنُ أَبِي مُلَيْكَةَ، عَنْ عُقْبَةَ بْنِ الْحَارِثِ، أَنَّهُ تَزَوَّجَ ابْنَةً لأَبِي إِهَابِ بْنِ عَزِيزٍ، فَأَتَتْهُ امْرَأَةٌ فَقَالَتْ إِنِّي قَدْ أَرْضَعْتُ عُقْبَةَ وَالَّتِي تَزَوَّجَ بِهَا‏.‏ فَقَالَ لَهَا عُقْبَةُ مَا أَعْلَمُ أَنَّكِ أَرْضَعْتِنِي وَلاَ أَخْبَرْتِنِي‏.‏ فَرَكِبَ إِلَى رَسُولِ اللَّهِ صلى الله عليه وسلم بِالْمَدِينَةِ فَسَأَلَهُ، فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ كَيْفَ وَقَدْ قِيلَ ‏"‏‏.‏ فَفَارَقَهَا عُقْبَةُ، وَنَكَحَتْ زَوْجًا غَيْرَهُ

Narrated By 'Abdullah bin Abi Mulaika : 'Uqba bin Al-Harith said that he had married the daughter of Abi Ihab bin 'Aziz. Later on a woman came to him and said, "I have suckled (nursed) Uqba and the woman whom he married (his wife) at my breast." 'Uqba said to her, "Neither I knew that you have suckled (nursed) me nor did you tell me." Then he rode over to see Allah's Apostle at Medina, and asked him about it. Allah's Apostle said, "How can you keep her as a wife when it has been said (that she is your foster-sister)?" Then Uqba divorced her, and she married another man.