Musnad Ahmad 28:43

Ibn Numayr narrated to us, al-A‘mash narrated to us, from ‘Uthman ibn ‘Umayr Abu al-Yaqzan, from Abu Harb ibn Abi al-Aswad, who said: I heard ‘Abdullah ibn ‘Amr say: I heard the Messenger of Allah (peace and blessings of Allah be upon him) say: "The dust has not carried, nor has the sky shaded, a man more truthful than Abu Dharr."