Musnad Ahmad 30:1898

'Affan narrated to us, Abu 'Awanah narrated to us, from 'Umar ibn Abi Salamah, from his father, from Abu Hurairah, from the Prophet, peace and blessings of Allah be upon him, who said: "Whoever takes a span of land without right, it will be encircled around his neck from seven earths."