Musnad Abu Ya'la al-Mawsili 115:310

Ubayd Allah narrated to us, Khalid narrated to us, Husayn al-Mu'allim narrated to us, he said: I heard Qatadah narrating from Anas ibn Malik, that the Messenger of Allah (peace and blessings of Allah be upon him) said: "By the One in Whose hand is the soul of Muhammad, none of you believes until he loves for his brother what he loves for himself of good."