It is narrated from Umm al-Mu'mineen Sayyidah Aisha (may Allah be pleased with her) that she said: "It was revealed in the Qur'an that ten times suckling establishes prohibition (of marriage), then this was abrogated and (the command came) that five times suckling establishes prohibition. When the Messenger of Allah (peace and blessings be upon him) passed away, this was among the verses that were recited in the Qur'an."
Hadith Referenceمسند الإمام الشافعي / كتاب النكاح / 1180