It was revealed in the Qur'an that: ten times of breastfeeding known with certainty establish prohibition (Mahram relationship through breastfeeding); then that was abrogated and replaced with five times of breastfeeding known with certainty. The Messenger of Allah (may Allah's peace and blessings be upon him) died while these (words of the abrogating verse) were still being recited as part of the Qur'an