It is narrated from Sayyiduna Ali (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Even if only one day remains for the end of the world, Allah Almighty will surely send a man from among us who will fill the earth with justice and fairness just as it had previously been filled with oppression and tyranny." (The reference is to Sayyiduna Imam Mahdi, may Allah be pleased with him, about whom a separate book by this humble author titled "The Concept of Imam Mahdi in Islam" is available in the market.)