SHAFAQNA – Allameh Majlesi said: Some narrators were present when Ali ibn Hamza, Ibn Seraj and Ibn Makareh came to Imam Reza (AS) and discussed about his Imamate. Ali ibn Hamza said: It is narrated from your fathers that no one can bury an Imam except another Imam. Ali ibn Hamza asked Imam Reza (AS), was Hossain ibn Ali (AS) an Imam or not? Imam Reza (AS) replied: Yes, he was Imam. Ali ibn Hamza asked: Who buried him? Imam Reza (AS) replied: Ali ibn Hussain (AS) (Imam Sajjad (AS)).
Ali ibn Hamza asked: Where was he? He was the captive of Ibn Ziad! Imam Reza replied: He came out without his captors noticing and buried his father and then returned. Imam (AS) continued by saying: The God who is capable of taking Imam Sajjad (AS) to Kufa, to bury his father, is able to take Imam (meaning himself) who is neither in prison nor a captive to Baghdad to bury his father (Imam Mosa Kazim (AS)) and then return .
 Beharul Anwaar, Vol. 42, page 187.