Musnad Ahmad 33:1146

Ya'mar narrated to us, Abdullah informed us, Hisham informed us, he said: I heard al-Hasan mentioning from Jabir ibn Abdullah, he said: The Messenger of Allah, may Allah bless him and grant him peace, said: "Indeed, for every prophet there is a supplication which he has supplicated with. And I have reserved my supplication as an intercession for my nation on the Day of Resurrection."