Musnad Ahmad 27:1290

'Arim narrated to us, 'Abdullah ibn al-Mubarak narrated to us, Musa ibn 'Uqbah narrated to us, from Salim, from Ibn 'Umar, from the Prophet, peace and blessings of Allah be upon him, who said: "Whoever takes anything from the land unjustly, he will be swallowed down to the seven earths."