The second among the four special deputies of His Eminence Imam Mahdi (may Allah hasten his noble reappearance), Muhammad Ibn Usmaan Ibn Saeed al-Amri (may Allah have mercy upon him) was asked:
“Have you seen the master of this affair viz. Imam Mahdi (may Allah hasten his noble reappearance)?”
He replied: “Yes, my last meeting with him was near the Sacred House of Allah (Holy Kaabah) while he was praying,
اللّٰهُمَّ أَنْجِزْ لِيْ مَا وَعَدْتَنِيْ
“O Allah! Fulfil for me whatever You have promised me.”
[Behaar al-Anwaar, vol. 52, p. 30, H. 23 narrating from Kamaaluddin]
It is found in another tradition that Imam Mahdi (may Allah hasten his noble reappearance) was holding on to the cloth of the Holy Kaabah while saying,
اللّٰهُمَّ انْتَقِمْ مِنْ أَعْدَائِيْ
“O Allah! Take revenge from my enemies.”
[Behaar al-Anwaar, vol. 52, p. 30, H. 23 narrating from Kamaaluddin]
We recite a similar statement in Ziyaarat of Arbaeen of Imam Husain (peace be upon him). A visitor of Imam Husain (peace be upon him) confesses to him in the Arbaeen Ziyaarat thus:
وَ أَشْهَدُ أَنَّ اللهَ مُنْجِزٌ لَكَ مَا وَعَدَكَ وَ مُهْلِكٌ مَنْ خَذَلَكَ وَ مُعَذِّبٌ مَنْ قَتَلَكَ
“And I bear witness that Allah will fulfil for you whatever He has promised you; He will destroy the one who abandoned you and punish the one who killed you.”
It means after Ziyaarat of Aashoora and Dua Nudba, it is evident that there is a special bond between Imam Mahdi (may Allah hasten his noble reappearance) and Imam Husain (peace be upon him). Imam Mahdi (may Allah hasten his noble reappearance) is not just the inheritor of Imam Husain (peace be upon him) but also the avenger of his blood. It is evident from both these traditions and this statement of the Arbaeen Ziyaarat how important it is for those who mourn the martyrdom of Imam Husain (peace be upon him) to pray for the early reappearance of Imam Mahdi (may Allah hasten his noble reappearance).
Since Imam Mahdi (may Allah hasten his noble reappearance) himself has been praying for revenge from the killers of Imam Husain (peace be upon him) and his own reappearance for the past approximately 1200 years, imagine how fervently should the lovers of Imam Husain (peace be upon him), his mourners and his visitors be praying for the early reappearance of Imam Mahdi (may Allah hasten his noble reappearance).
O Allah! For the sake of the oppression on Imam Husain (peace be upon him), hasten the reappearance of the avenger of Imam Husain (peace be upon him) and the Imam of our time, His Eminence Imam Mahdi (may Allah hasten his noble reappearance). Grant us the good fortune of praying for his reappearance in the mausoleum of Imam Husain (peace be upon him) while holding on to his shrine, and grant us the opportunity to take revenge on his enemies after his reappearance.
Aameen, O Lord of the worlds!