Musnad Ahmad 32:1930

Muhammad ibn Ja'far narrated to us, Shu'bah narrated to us, and Hajjaj narrated to us, he said: Shu'bah narrated to me, he said: I heard Qatadah narrating from Anas ibn Malik, from the Prophet, may Allah bless him and grant him peace, that he said: "None of you believes until he loves for his brother - or his neighbor - what he loves for himself." And Hajjaj did not express doubt: "until he loves for his brother what he loves for himself."