Musannaf Ibn Abi Shayba 3:6206

Waki’ narrated to us, he said: ‘Abdullah bin ‘Abdur-Rahman bin Ya’la al-Ta’ifi narrated to us, from ‘Uthman bin ‘Abdullah bin Aws al-Thaqafi, from his grandfather Aws bin Hudhayfah, he said: We arrived to the Messenger of Allah (may Allah bless him and grant him peace) with the delegation of Thaqif. He said: He lodged us in a tent of his, and our brothers, the Ahlaf, lodged with al-Mughirah bin Shu’bah. He said: The Messenger of Allah (may Allah bless him and grant him peace) used to come to us after the night prayer (‘Isha) and speak with us. Most of his speech was complaining about Quraysh, and he would say: "We were not equal while we were in Makkah, except as oppressed and humiliated. When we came to al-Madinah, the war was alternating between us and them." He said: Then he was late for us one night, and it was prolonged, so we said: "O Messenger of Allah, you were late for us." He said: "A portion (hizb) of the Qur’an occurred to me, and I disliked to leave until I had completed it." We asked the companions of the Messenger of Allah (may Allah bless him and grant him peace) about how he divided the Qur’an. They said: "He used to divide it into three, five, seven, nine, eleven, thirteen, and the division of the Mufassal."