Musnad Ahmad 30:2168

'Affan narrated to us, he said: Hammad narrated to us, Thabit narrated from Abu Rafi', from Abu Hurayrah—Hammad said: I do not know it except that he attributed it to the Prophet, then Hammad said: I believe it is from the Prophet, may Allah bless him and grant him peace—"A man visited a brother of his in another village. Allah set an angel in wait for him on his path. When he came upon him, the angel said: 'Where do you intend to go?' He said: 'I am visiting a brother of mine in this village.' He said: 'Is there any favor of his upon you that you are nurturing?' He said: 'No, except that I have loved him for the sake of Allah, the Almighty and Majestic.' He said: 'Indeed, I am a messenger of Allah to you, [informing you] that Allah, the Almighty and Majestic, has loved you just as you have loved him.'"