Musannaf Ibn Abi Shayba 1:1102

Abu Mu'awiyah narrated to us, from al-A'mash, from Salamah ibn Kuhayl, from Sa'id ibn Jubayr, from Ibn Abbas and Ibn Umar, he said: They both used to recite their portions of the Qur'an after they would exit from the privy, before they performed ablution.