Musnad Ahmad 1153:1376

Muhammad ibn Ja'far narrated to us, he said: Shu'bah narrated to us, and Hajjaj said: Shu'bah narrated to me, from 'Abd al-Rahman ibn al-Qasim, from his father, from 'Aishah, that she said: "I used to perform ghusl (ritual bath), I and the Messenger of Allah, may Allah bless him and grant him peace, from a single vessel, due to janabah (major ritual impurity)."