Ibn Sa'd

"Ali Ibn Abi Talib, said: Verily the Prophet said: God divided the earth in two halves and placed (me) in the better of the two, then He divided the half in three parts, and I was in the best of them, then He chose the Arabs from among the people, then He chose the Quraysh from among the Arabs, then He chose the children of ‘Abd al-Muttalib from among the Banu Hashim, then he chose me from among the children of ‘Abd al-Muttalib, and from them he chose me."

"We were headed toward and 'Umar accompanied us as far as Sirar. Then he made ablutions, washing twice, and said: "Do you know why I have accompanied you?" We said: "Yes, we are companions of God's messenger (peace and blessings be upon him)." Then, he said: You will be coming to the people of a town for whom the buzzing of the Qur'an is as the buzzing of bees. Therefore, do not distract them with the Hadiths, and thus engage them. Bare the Qur'an and spare the narration from God's messenger (peace and blessing be upon him)!"