Musnad Ahmad 32:2167

'Ali ibn 'Abdullah narrated to us, Mu'adh ibn Hisham narrated to us, he said: My father narrated to me, from Qatadah, Anas ibn Malik narrated to us, that the Prophet of Allah, may Allah bless him and grant him peace, said: "Indeed, for every prophet there is a supplication, and I have reserved my supplication as an intercession for my nation on the Day of Resurrection." End of the Musnad of Anas ibn Malik, may Allah be pleased with him.