Musnad Ahmad 1153:152

Abu Bakr ibn Ayyash narrated to us, he said: Al-A’mash narrated to us, from Abu Ishaq, from Al-Aswad, from Aisha, she said: "The Messenger of Allah, peace and blessings of Allah be upon him, would be in a state of major ritual impurity (junub), then he would sleep, and he would not touch water until he would rise after that, then he would perform ghusl."