Musnad Ahmad 1153:588

Hashim ibn al-Qasim narrated to us, he said: Mubarak narrated to us, from al-Hasan, from Sa'd ibn Hisham ibn 'Amir, who said: I came to 'Aishah and said: "O Mother of the Believers, inform me about the character of the Messenger of Allah, peace and blessings of Allah be upon him." She said: "His character was the Qur'an. Do you not read the Qur'an, the saying of Allah, the Almighty and Majestic: 'And indeed, you are of a great moral character' [Al-Qalam: 4]?" I said: "I intend to practice celibacy (tabattul)." She said: "Do not do that. Do you not read: 'There has certainly been for you in the Messenger of Allah an excellent pattern' [Al-Ahzab: 21]? For the Messenger of Allah, peace and blessings of Allah be upon him, married, and children were born to him."