Musnad Ahmad 1153:1618

'Abd al-Razzaq narrated to us, Ma'mar narrated to us, from al-Zuhri, from 'Urwah, from 'Aishah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) used to pray the 'Asr prayer while the sun was still rising (i.e., shining) inside my chamber before it had departed.