The Sermon which Imam Reza(A.S.) has written to al-Ma'mun
Al-Ma'mu`n asked Imam al-Reza`, peace be on him, to write him a sermon in order to recite it to the people when he led them in prayer, so he, peace be on him, wrote him the following great sermon:
"In the name of Allah, the Most Gracious, the Most Merciful.
"Praise belongs to Allah, Who from nothing was, nor from making a thing He sought help, nor from a thing He created (the creatures), nor from it He formed the things; rather He said to it, "Be," and it is.
"And I bear witness that there is no god but Allah, Who is unique and without partners, far above resisting rivals, vying with opposites, taking consorts and children. I also bear witness that Mohammed is His chosen servant and his distinguished, trusted one.
He sent him with the detailed Qur'a`n, His connected revelation, and His pure Distinguisher (Furqan), so he gave good news of His reward and warned against His punishment, may Allah bless him and his family.
"I recommend you, O servants of Allah, to fear Allah, Who knows your secret and open (deeds), and knows what you hide, so surely Allah will not leave you wandering without an aim; nor did He create you in vain; nor will He enable you to guidance. Beware! Beware, servants of Allah! For Allah has made you cautious of (retribution from) Himself, so do not subject (yourselves) to regret, calling for wrath, and arriving at the torture of the Hellfire, surely the torture thereof is a lasting evil, surely it is an evil abode and (evil) place to stay; it does not go out; eyes do not sleep; souls neither die nor live; (they are) in chains and shackles, (subjected to) punishments and exemplary punishments, so oft as their skins are thoroughly burned, We will change them for other skins, that they may taste the chastisement; surely Allah is Mighty, Wise; a fire, the smoke of which shall encompass them about, so their call shall not be heard, their supplication shall not be responded, and there shall be no mercy upon their weeping.
So flee, O servants of Allah, to Allah through these perishing souls, in the successive outcry, in the bygone days, before death befalls you, usurps your souls from you, distresses you in your hearts and be between you and the return. How far! So there will be no way to the return and no arrival to the residence. May Allah protect you and me through what He has protected His righteous friends, guide you and me to what He has guided His good servants. "
This sermon summons men to do good, to refrain from the unlawful, and to renounce the world; it warns them against Allah's punishment and chastisement (Al-Durr al-Nazim, p. 215).