Al-Kharaij: It is narrated from Abul Hasan Mustariq Zarir that he said:
“I was present in the assembly of Hasan bin Abdullah bin HamadanNasirud Daula and we mentioned the matter of Imam Zamana (a.s.) and Imade fun of it. Meanwhile one day, my uncle, Husain paid a visit to me and Idiscussed the same topic with him. He said: Son, I was also having the sameview before. Once I was appointed as a governor of Qom, since the Sultanwas in trouble and anyone who came to Qom on behalf of him was chasedaway by the people there.
So I was given an army and I set out for Qom. When I reached the Tarzprovince I camped there for sometime. One day when I went hunting, I came across a river. I climbed into it and continued to follow the prey. As much as Imoved ahead, the stream deepened and widened and then I saw a ridermounted on a red horse, in such a way that only his eyes were visible and he was wearing red socks. As soon as he came, he called out: O Husain. That ishe neither addressed me by my title or my patronymic; on the contrary hecalled me in an insulting manner. I asked: What do you want?
He replied: Why do you make fun of Imam Mahdi (a.s.) and why do younot pay the Khums to my men?
Husain says: Although I was a brave and daring man, the awe of thatrider overcame me and I began to fear a little. Yet I put up a brave face andsaid: My lord, I will do as you say.
He said: All right, you may go wherever you like, but you must pay theshare of the deserving from whatever you receive.
I accepted with all humility.
Then he said: Go on, may Allah guide you to the right path.
Saying this, he turned his horse and went away. I looked here and there,but he had suddenly disappeared. Afterwards I forgot about that incident.
When I reached Qom, I realized that I would have to fight that community. But as soon as I reached there, the people of Qom came to meand said: We opposed all the governors so far. But now that you have come,we don’t intend to fight you. You may come in a take over the administration.
So I remained there and made unexpected wealth, but the army chiefscomplained to the Sultan about me and they were jealous that I was livingthere since years and making money.
Hence I was dismissed and I returned to Baghdad. I first attended thecourt of the Sultan and then came home. People came to meet me. Amongthem was Muhammad bin Uthman Amari (who was one of the four specialdeputies of Imam Zamana (a.s.)). He came and sat down reclining on mypillow, which I found to be extremely audacious. People continued to comeand go and my anger continued to increase. When all had left, he came to meand said: I want to speak to you in private. “You may say what you like.”
He said: “Once you had met a rider on a red horse in a stream. Hismessage for you is that he has fulfilled his promise. You must also fulfillyours.”
As soon I heard this, I recalled that incident and I began to tremble. AndI said: “With all humility.” Then I arose, held his hand and brought him to my treasure trove. He started taking out a fifth of everything till he calculated the Khums of the monies that I had forgotten. After that he went away.
After this incident, in my view, the existence of the Master of the Affairwas confirmed for me and no doubt remained in my mind.
The narrator says: Since I heard this from my uncle, my doubt was alsodispelled.
Reference : Beharul anwar vol 51.52.53 , Part 1 , The Promised Mahdi