Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) said: I said: "O Messenger of Allah, which injustice is the greatest?" He (peace and blessings be upon him) said: "A cubit of land that a believer takes away from the right of his brother; every single pebble of it will be made into a collar around his neck on the Day of Resurrection."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 10470