Musnad Ahmad 1015:22

Waki’ narrated to us, from Sharik, from ‘Abdullah ibn Muhammad ibn ‘Aqil, from ‘Ata’ ibn Yasar, from Abu Malik al-Ash’ari, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The greatest of betrayal (ghulul) in the sight of Allah on the Day of Resurrection is a cubit of land that is between two men or between two partners of a house, so they divide it, and one of them steals a cubit of land from his companion. He will be made to wear it [as a collar] from seven earths."