Musnad Abu Ya'la al-Mawsili 115:109

Ubayd Allah ibn Mu'adh al-'Anbari narrated to us, my father narrated to us, Shu'bah narrated to us, from Qatadah, from Anas ibn Malik, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "None of you believes until he loves for his brother what he loves for himself."