Musnad Ahmad 937:188

Muhammad ibn Ja'far narrated to us, Shu'bah narrated to us, he said: I heard Abu 'Imran al-Jawni narrating from 'Abdullah ibn al-Samit, from Abu Dharr, he said: I said: "O Messenger of Allah, a man does a deed for himself, and the people love him for it?" He said: "That is the immediate glad tiding of the believer."