Musnad Ahmad 31:336

'Abd al-Razzaq narrated to us, Ja'far narrated to us, from al-Mu'alla ibn Ziyad, al-'Ala' ibn Bashir narrated to us, from Abu al-Siddiq al-Naji, from Abu Sa'id al-Khudri, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "I bring you glad tidings of the Mahdi. He shall be sent forth in my Ummah at a time of disagreement among the people and earthquakes. He shall fill the earth with equity and justice, just as it was filled with oppression and tyranny. The dweller of the heaven and the dweller of the earth shall be pleased with him. He shall distribute wealth correctly (sahahan)." A man said to him: "What is 'sahahan'?" He said: "Equally among the people." He said: "And Allah shall fill the hearts of the Ummah of Muhammad (peace and blessings of Allah be upon him) with richness, and his justice shall encompass them, until he commands a herald to call out, saying: 'Who has a need for wealth?' No one among the people shall stand except for one man, who will say: 'I.' He will say: 'Go to the treasurer (al-sadan) and tell him: The Mahdi commands you to give me wealth.' He will say to him: 'Scoop.' Until, when he has placed it in his garment and brought it out, he will regret it. He will say: 'I was the greediest of the Ummah of Muhammad in soul, or was I unable to contain what sufficed them?' He said: 'So he will return it, but it will not be accepted from him. It will be said to him: We do not take back anything we have given.' It shall be like that for seven years, or eight years, or nine years. Then there is no good in life after him," or he said: "Then there is no good in living after him."