(51) باب الْقَدْرِ الَّذِي يُحَرِّمُ مِنَ الرَّضَاعَةِ .
It was narrated that 'Aishah said:
"One of the things that Allah, the Mighty and Sublime, revealed" -(one of the narrators) Al-Harith said (in his narration): "One of the things that were revealed in the Qur'an"- "was that ten known breast-feedings make marriage prohibited, then that was abrogated and changed to five known breast-feedings. Then the Messenger of Allah passed away when this was something that was still being recited in the Qur'an."
Reference: Sunan an-Nasa'i 3307
In-book reference: Book 26, Hadith 112
English translation: Vol. 4, Book 26, Hadith 3309