Musnad Abu Ya'la al-Mawsili 209:124

Abu Khaythama narrated to us, Muhammad ibn Khazim narrated to us, from Musa ibn Ubaydah al-Rabadhi, from Sa'id ibn Abd al-Rahman ibn Abi Ayyash al-Zuraqi, from Anas ibn Malik, from Umm Salamah, the wife of the Prophet (may Allah bless him and grant him peace), who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "I was shown what my Ummah will do after me, so I chose intercession for them until the Day of Resurrection."