Musnad Ahmad 937:225

Hassan narrated to us, Ibn Lahi'ah narrated to us, Yazid ibn Abi Habib narrated to us, that Abu Salim al-Jayshani came to Abu Umayyah in his house and said: "I heard Abu Dharr saying that he heard the Messenger of Allah, peace and blessings of Allah be upon him, saying: 'If one of you loves his companion, let him come to him in his house and inform him that he loves him for the sake of Allah, the Almighty and Majestic.' And I have loved you, so I have come to you in your house."