Musnad Ahmad 1153:1913

Ibn Numayr narrated to us, from ‘Abd al-Malik, from ‘Ata’, from ‘A’ishah, who said: "The Messenger of Allah (peace and blessings of Allah be upon him) would be struck by janabah (major ritual impurity) at night while he intended to fast. He would sleep and wake up, and he would reach the morning in a state of janabah, then he would pour water over himself, then he would perform wudu’."