Translation of the letter:
His honor Mansoor Hashemi Khorasani wrote in a letter for Umair ibn Ahmad Hussaini one of his helpers in Khorasan:
“In the Name of Allah the beneficent the most merciful
And so next; Oh son of Ahmad! Indeed the example of me among the people of Khorasan is similar to Muslim ibn Aqil among people of Iraq; so see how you treat me; because, I swear to God, Mahdi will rise for what Hussain rose for and whoever helps Mahdi is equal to one who has helped Hussain and salvation is for one who is loyal to his promise with him; Peace”.
Explanation of the letter:
Abu al-Faraj al-Isfahani (Died in 356 AH) has quoted in the book of Maqatil al-Talibiyyeen: «لمّا بلغ أهل الكوفة نزول الحسين عليه السّلام مكّة وأنّه لم يبايع ليزيد، وفد إليه وفد منهم عليهم أبو عبد اللّه الجدليّ، وكتب إليه شبث بن ربعيّ وسليمان بن صرد والمسيّب بن نجية ووجوه أهل الكوفة يدعونه إلى بيعته وخلع يزيد، فقال لهم الحسين: <أَبْعَثُ مَعَكُمْ أَخِي وَابْنَ عَمِّي، فَإِذَا أَخَذَ لِي بَيْعَتِي وَأَتَانِي عَنْهُمْ بِمِثْلِ مَا كَتَبُوا بِهِ إِلَيَّ قَدِمْتُ عَلَيْهِمْ>، ودعا مسلم بن عقيل فقال له: <اشْخَصْ إِلَى الْكُوفَةِ، فَإِنْ رَأَيْتَ مِنْهُمُ اجْتِمَاعًا عَلَى مَا كَتَبُوا، وَرَأَيْتَهُ أَمْرًا تَرَى الْخُرُوجَ مَعَهُ، فَاكْتُبْ إِلَيَّ بِرَأْيِكَ>، فقدم مسلم الكوفة، وأتته الشيعة، فأخذ بيعتهم للحسين»; “When people of Kufa were informed that Husain peace be upon him has gone to Kufa and has not pledged allegiance to Yazid, some representatives from them were sent to him that Abu Abdullah al-Jadali was at the head of them, and Shabath ibn Raba’i and Sulayman ibn Surad and Musayyib ibn Najyah and other elders of Kufa corresponded with him and demanded allegiance to him and deposition of Yazid. Then Husain said to them: ‘I will send my brother and my cousin with you. So if he takes allegiance for me and reports to me what (people of Kufa) wrote, I will go to them’. Then he called Muslim ibn ‘Aqil and said to him: ‘Go to Kufa. So if you see that they have agreement on what they have written and see it suitable for the uprising, write me your opinion’. So Muslim came to Kufa and the Shia came to him and he took allegiance from them for Husain”. Then he has narrated their story to the point that they left him alone and surrendered him to ‘Ubaydullah ibn Zyad, in a way that when he, may God have mercy on him, became sure of his death, he did not find anyone to whom make a will and had to make a will to one of his enemies who was related to him and told him: «ابْعَثْ إِلَى الْحُسَيْنِ مَنْ يَرُدُّهُ»; “Send someone to Husain to have him return”. So, what his Honor Mansoor may God protect him, means by this allegory is that just as Muslim ibn ‘Aqil came to Iraq to prepare the grounds for the sovereignty of Husain, his Honor has come to Khorasan to prepare the grounds for the sovereignty of Mahdi as well, and just as Muslim ibn ‘Aqil took allegiance from people of Iraq for Husain, his Honor takes allegiance from people of Khorasan for Mahdi as well, and just as people of Iraq forsaking Muslim ibn ‘Aqil prevented Husain from coming to power, people of Khorasan forsaking his Honor will prevent Mahdi from coming to power as well and with this description, one must learn lessons from history to prevent its recurrence, and this is based on the words of God Almighty that has said: ﴿لَقَدْ كَانَ فِي قَصَصِهِمْ عِبْرَةٌ لِأُولِي الْأَلْبَابِ ۗ﴾; “Indeed, there are lessons in their stories for the wise people” and has said: ﴿قُلْ سِيرُوا فِي الْأَرْضِ فَانْظُرُوا كَيْفَ كَانَ عَاقِبَةُ الَّذِينَ مِنْ قَبْلُ ۚ﴾; “Say, travel through the earth and see what was the end of those who came before”.