Imam Rida (peace be upon him): Aba Salt Abd al-Salam ibn Salih al-Harawi said: One day Ma'mun asked Imam Rida (peace be upon him): "O son of the Messenger of Allah (peace be upon him and his family)! What is the meaning of the verse وَ لَوْ شَاء رَبُّکَ لآمَنَ مَن فِی الأَرْضِ کُلُّهُمْ جَمِیعًا أَفَأَنتَ تُکْرِهُ النَّاسَ حَتَّی یَکُونُواْ مُؤْمِنِینَ، وَ مَا کَانَ لِنَفْسٍ أَن تُؤْمِنَ إِلاَّ بِإِذْنِ الله [And if your Lord had pleased, surely all those who are in the earth would have believed, all of them; will you then force men till they become believers? And it is not for a soul to believe except by Allah's permission]?" Imam Rida (peace be upon him) said: "My father Musa ibn Ja'far (peace be upon him) narrated from his father Ja'far ibn Muhammad (peace be upon him) from his father Muhammad ibn Ali (peace be upon him) from his father Ali ibn Husayn (peace be upon him) from his father Husayn ibn Ali (peace be upon him) from his father Ali ibn Abi Talib (peace be upon him) who said: 'The Muslims said to the Messenger of Allah (peace be upon him and his family): "If you had forced some of the people whom you were able to make Muslims to accept the religion of Islam, our number would have grown greater and we would have prevailed over our enemies!" The Messenger of Allah (peace be upon him and his family) said: "I am not one to meet Allah the Exalted with an innovation about which He has not given me any instruction, and I am not one who compels anyone to any deed." Then Allah, Blessed and Exalted, revealed this verse to him: "O Muhammad (peace be upon him and his family), وَ لَوْ شَاء رَبُّکَ لآمَنَ مَن فِی الأَرْضِ کُلُّهُمْ جَمِیعًا [And if your Lord had pleased, surely all those who are in the earth would have believed, all of them] — by way of compulsion and force in this world [He would have made them believers]; just as they will believe on the Day of Resurrection at the moment they witness the terror and dread of that Day. And if I had drawn them into the valley of faith by compulsion, they would no longer have deserved My reward, recompense and praise. I want them to believe by their own choice and free will, not by force and compulsion, so that they may deserve nearness to My presence, honour, dignity and eternity in Paradise. أَفَأَنتَ تُکْرِهُ النَّاسَ حَتَّی یَکُونُواْ مُؤْمِنِینَ [Will you then force men till they become believers?]."'"