Sahih Muslim
The Book of Marriage (Kitab Al-Nikah)
Book Number: 008 / Hadith Number: 3421
'A'isha (Allah be pleased with, her) reported that it had been revealed in the Holy Qur'an that ten clear sucklings make the marriage unlawful, then it was abrogated (and substituted) by five sucklings and Allah's Apostle (may peace be upon him) died and it was before that time (found) in the Holy Qur'an (and recited by the Muslims).