Imam Ali (peace be upon him): A zindiq (heretic) came to the Master of the Monotheists, Amir al-Mu'minin (peace be upon him), and said, "Were it not for this discrepancy in the verses of your Quran, I would certainly have embraced your religion." The Imam said, "Which verse is that?" He said, "... I have found that He spoke of the superiority of His Prophet over the other prophets, and then, many times more than the praise He gave him, He addressed him with such humiliation, lowering of station, reproach and rebuke as He addressed none of the other prophets — such as where He said: 'But if Allah wills, He will gather them [by compulsion] on guidance. [Yet what benefit is there in forced guidance?] So never be of the ignorant!' (al-An'am/35), and وَ لَوْ لا أَنْ ثَبَّتْناکَ لَقَدْ کِدْتَ تَرْکَنُ إِلَیْهِمْ شَیْئاً قَلِیلًا [And had it not been that We had already established you, you would certainly have been near to incline to them a little], and إِذاً لَأَذَقْناکَ ضِعْفَ الحَیاةِ وَ ضِعْفَ المَماتِ ثُمَّ لا تَجِدُ لَکَ عَلَیْنا نَصِیراً [In that case We would have made you taste a double portion in life and a double portion in death; then you would not have found for yourself any helper against Us]...".
Imam Ali (peace be upon him) said: "... As for the address you mentioned which indicates reproach, rebuke and blame of the Noble Prophet (peace be upon him and his family) — even though Allah the Blessed and Exalted made his superiority over the rest of His prophets manifest in His Book — Allah the Mighty and Majestic, as He said in His Book, appointed for every prophet an enemy from among the criminals, and in view of the greatness of the station of our Prophet (peace be upon him and his family) with his Lord, Allah the Exalted made the trial he endured from his enemy more severe. An enemy who, in division and hypocrisy, spared no harm or torment against him in order to reject his prophethood and to make him appear a liar, and who strove to injure him and sought to shatter everything he had firmly established, and who, along with his supporters in disbelief, contention, hypocrisy and heresy, struggled to nullify his call, to alter his community and to oppose his sunnah. He employed his cunning to the utmost to turn the Ummah away from allegiance (walayah) to his successor (wasi), to separate them from him, to prevent them from joining him, to incite them to enmity against him, and he wished to alter the Book which he had brought and to remove from it what it contained of the merit of the people of merit and the disbelief of the people of disbelief such as himself and his helpers in oppression, tyranny and shirk. Allah knew that they would do this, and said: 'Indeed, those who distort Our verses are not concealed from Us!' (Fussilat/40). And Allah the Mighty and Majestic also says elsewhere: 'They wish to change the word of Allah.' (al-Fath/15). They brought the Book while it was complete, containing ta'wil (esoteric interpretation) and tanzil (revelation), the muhkam (clear) and the mutashabih (ambiguous), the nasikh (abrogating) and the mansukh (abrogated), and not a single alif or lam of it had been dropped. Then, when they came upon the names by which Allah had identified the people of truth and falsehood in it, and realised that if these names appeared the pact they had bound would be broken, they said, 'We have no need of this, and what we have suffices us from it.' Allah said: 'But they cast it behind their backs and sold it for a paltry price — how evil is what they buy!' (Aal Imran/187). Then, from matters whose ta'wil they did not know, problems arose for them, and so they were compelled to gather it and compile it and add to it, from themselves, things upon which the pillars of their disbelief could be built. At that moment their crier called out, 'Whoever has anything of the Quran with him, let him bring it to us.' Then they entrusted the compilation and arrangement of the Quran to one who was, in enmity toward the awliya', their partisan and helper, and he compiled the Book according to their choice — in such a way that they abandoned what they thought was in their favour, although it was actually against them, and added things in it which were plainly repugnant and inconsistent. And Allah knew that this would appear and become manifest, and said: 'That is the limit of their knowledge.' (al-Najm/30). Allah the Exalted exposed their defectiveness and the fabrication of the one who, in the Book, brought forth reproach of the Noble Prophet (peace be upon him and his family) through heretical falsification, and said: 'They speak an evil and false word.' (al-Mujadila/2). And Allah the Exalted made known to His Prophet (peace be upon him and his family) what his enemy would introduce into this Book after him, and said: 'And We did not send before you any messenger or prophet except that, when he had a wish [and drew up a plan to advance his divine aims], Satan would cast [something] into his wish; but Allah nullifies what Satan casts, then Allah makes His verses firm.' (al-Hajj/52). That is: whenever a prophet wished to depart from the disobedience and hypocrisy he saw in his people and to be transferred to the abode of permanence, Satan would make his enmity with him apparent, and after his passing would cast doubts into the Book that had been sent down upon him, in which reproach, rebuke and censure of Satan had come down. But Allah would remove that from the hearts of the believers, so their hearts would not accept it — and only the hearts of the hypocrites and the ignorant would lend it an ear. Allah — may His remembrance be majestic and exalted — made His verses firm in this way, protecting His friends against misguidance, enemies, and the followers of the people of disbelief and disobedience, those with whom Allah was not content to place them like cattle [rather, He placed them lower than cattle], and said: 'Rather, they are more astray!' (al-Furqan/44). So understand this and act upon it, and know that whatever you had, you asked; and I have contented myself with a brief exposition out of much, for there are no bearers of this knowledge, and those who desire to receive this knowledge are few, and in less than what I have set forth for you there is a sufficient message for those of understanding." The man said: "What I have heard from you suffices me, O Amir al-Mu'minin!"