Musnad Ahmad 1153:1409

Muhammad ibn Ja'far narrated to us, Shu'bah narrated to us, from al-Hakam, who said: I heard Ibrahim narrating from al-Aswad, from 'Aishah, that she said: "It is as if I am looking at the glistening of the perfume in the parting of the hair of the Messenger of Allah, may Allah bless him and grant him peace, while he was in the state of ihram."