After poisoning Imam Riḍā (P.B.U.H.), Ma’mūn showed false sadness and impatience for the death of the Imam (P.B.U.H.). He went out bare-footed and headed. He struck his head, seized his beard, wept, and said at the top of his voice, “By Allah! I do not know which of the two calamities is greater: Losing you and parting from you, or people’s accusation that I assassinated and killed you.”
Ma’mūn displayed sorrow for the death of the Imam (P.B.U.H.) in order to rid himself of the accusation of assassinating him, but, shortly after that, the people came to know of his pretense and became fully aware of that it was he who assassinated him. Ma’mūn committed this crime in order to get rid of the Imam (P.B.U.H.), for his reputation spread all over Islamic world, the proofs of his Imamate were clear, the Muslims loved him, he had moral traits and exalted manners, clung to Allah, renounced the world, and other qualities, whereas Ma’mūn and the rest of Abbasid kings were void of any noble inclination and exalted quality.
The holy body was brought to its final resting place under a halo of exclaiming, “Allah is the Greatest!” and magnification. His grave was digged beside the grave of Hārūn, who killed the Imam’s father (P.B.U.H.). Then Ma’mūn buried the Imam (P.B.U.H.) in the grave and buried along with him all excellent qualities and noble inclinations through which people become sublime.
Then the people came and condoled with Ma’mūn, the rest of the Alawites and the Abbasids on their painful misfortune. Sadness and sorrow melted all hearts of the people, for they lost the Imam of the Muslims (P.B.U.H.), the master of the God-fearing and those who turned to Allah in repentance. It is worth mentioning that Ma’mūn asked the people about the reason for burying the Imam (P.B.U.H.) beside the grave of his father, and they answered him,
“Because Allah will forgive Hārūn on account of his neighboring Imam Riḍā (P.B.U.H.).”However, the inspired poet, Diʿbil al-Khuzā’ī, has disproved this justification saying,
If you have a need in religion, then stop at Tus by the grave of the pure one wherein.
The nearness to the pure one does not benefit the unclean one; nor does the nearness to the unclean one harm the pure one.
How far! Everyone is hostage to that which his own hands earn, so take or leave whatever you desire.
Two graves are at Tus: The grave of the best of all people and the grave of the wickedest of them; this is among moral lessons.