Musnad Ahmad 1153:1313

'Abd al-Razzaq narrated to us, Ma'mar narrated to us, from 'Ata' al-Khurasani, from Yahya ibn Ya'mar, who said: I asked 'Aisha: "Did the Messenger of Allah, peace and blessings of Allah be upon him, sleep while he was in a state of major ritual impurity (junub)?" She said to me: "Sometimes he would perform ghusl (ritual bath) before he slept, and sometimes he would sleep before he performed ghusl, but he would perform wudu (ablution)." He said: "Praise be to Allah who has placed ease in the religion."