It is narrated from Sayyiduna Abu Huraira (may Allah be pleased with him) that a man used to visit his (Muslim) brother in another town. On his way, there was an angel who said to him: "Where are you intending to go?" He replied: "I am going to visit my brother in another town." The angel asked: "Is there any favor of his upon you which you are mindful of?" He said: "No, but I love him for the sake of Allah." The angel said: "I am a messenger from Allah to you (He has said) that just as you love him for My sake, so do I love you."
Hadith Referenceمسند اسحاق بن راهويه / كتاب الفضائل / 545
Hadith Takhrij«مسلم ، كتاب البر والصلة ، باب فى فضل الحب فى الله ، رقم : 2567 . مسند احمد : 482/2 . صحيح ابن حبان ، رقم : 576 .»