Musnad Ahmad 1153:2144

Yahya ibn Adam narrated to us, he said: Isra'il narrated to us, from Abu Ishaq, from 'Abd al-Rahman ibn al-Aswad, from his father, from 'A'ishah, she said: "I used to perfume the Messenger of Allah, may Allah bless him and grant him peace, with the best perfume I could find, until I would see the glistening of the perfume on his head and his beard before he entered into the state of Ihram."