In The Name of Allah, The Most Beneficent, The Most Merciful
It has been narrated from Imam Muhammad Baqir (a.s.) that at the time of reappearance Imam Mahdi (a.t.f.s.) will send a Hashmite youth towards the inhabitants of Macca for the completion of argument. He will tell him:
Go to the dwellers of Macca and say: I am the representative of so and so who has sent me to you. He has said: We Ahle Bayt (a.s.) are a mercy, the rich deposits of prophetic mission and succession. We are from the family of Prophet Muhammad (s.a.w.a.s.) and the sons of Prophets (a.s.). We are the oppressed ones and victims of cruelty. We are sidelined. Since the time the Noble Messenger (s.a.w.a.s.) passed away our rights are being wasted. We seek assistance from you. You also come and help us.
In another tradition fifth Imam (a.s.) revealed the excerpts of Imam-e-Asr’s (a.t.f.s.) speech near the Kaaba. He says:
(O People) I place Allah as a witness over you. I adjure everyone, who hears my speech today, to inform the absent of it. I ask you with the right of Allah, the right of His messenger and with my right, for I have a right of kinship to the messenger of Allah, to support us and to protect us from those, who have wronged us. We have been wronged, offended, expelled from our homes, separated from our families, deprived of our rights and our honor and virtues have been distorted by the evil people.
The late Haaji Sayed Ismael Sharfee would say:
I had left my place to visit the revered holy places. I was busy praying inside the haram of the Chief of Martyrs (a.s.) and I went there because prayers of a visitor do get accepted near the headstone of Chief of Martyrs (a.s.). At that moment a wish in my heart took birth and that of gaining the honour of meeting my master Imam Mahdi (a.t.f.s.). I was busy praying when I suddenly sighted the luminous face. After conveying my salam, I said, ‘O my Master, who are you?’ He answered, ‘I am the most oppressed person of this world.’
Imam Husain (a.s.) in a state of spiritual inspiration told one of the ulema of Qum. “Our Mahdi (a.s.) is an oppressed one in his own era. Talk about it as much as possible and write about it as much as you can. Whatever you discuss about him is like as if you have remembered all the Infallibles (a.s.). Because all of them are one in terms of Infallibility, Wilayat and Imamate. But as this is Mahdi’s (a.s.) era he should be spoken about as much as possible. I once again emphasis that talk about our Mahdi (a.s.) as much as you can and write about him. Our Mahdi (a.s.) is an oppressed one. And whatever is read and written should be about him. 
 Behaarul Anwaar: 52: 307
 Al-Ghayba An Nomani : 81
 Translation of Sahife Mahdiyyah (a.s.) : 58
 Translation of Sahife Mahdiyyah (a.s.): (Inteshaaraat Daarus Saqlain0 58