Musannaf Ibn Abi Shayba 32:25

Waki' narrated to us, from Hammad bin Salamah, from Thabit, from Abu Rafi', from Abu Hurairah, from the Prophet (peace be upon him), who said: A man went out from a village to visit a brother of his in another village. He said: So Allah sent an angel to him, and he sat on his path. He said: "Where do you intend to go?" He said: "I intend to go to a brother of mine whom I am visiting for the sake of Allah in this village." He said: "Does he have any favor upon you that you are nurturing?" He said: "No, but I have loved him for the sake of Allah." He said: "I am the messenger of your Lord to you, [informing you] that He has loved you as you have loved him for it."