Recently, I came across an accusation regarding a sermon of Imam Ali asws where in Nawasib tried to cast doubts on Infallibility

We see what they wrote

In his Khutbah recorded in Nahj-Al Balaghah # 216, Ali RA Said:

فلا تكفوا عن مقالة بحق ، أو بعدل مشورة ، فإني لست في نفسي بفوق أن أخطىء ، ولا آمن ذلك من فعلي

“Do not evade me as the people of passion are (to be) evaded, do not meet me with flattery and do not think that I shall take it ill if a true thing is said to me, because the person who feels disgusted when truth is said to him or a just matter is placed before him would find it more difficult to act upon them. Don’t stop saying the Truth, or Just Advice, As I am not above making Mistakes, and I am not safe from making Mistakes in my Actions”.

Source: Nahjul Balagha, Sermon 216.

First of all, these nawasib have not given the complete sentence, since that would have destroyed the whole argument in the first go. The sermon says

 فَلاَ تَكُفُّوا عَنْ مَقَالَةٍ بِحَقٍّ، أَوْ مَشُورَةٍ بِعَدْلٍ، فَإِنِّي لَسْتُ فِي نَفْسِي بِفَوْقِ أَنْ أُخْطِىءَ، وَلاَ آمَنُ ذلِكَ مِنْ فِعْلِي، إِلاَّ أَنْ يَكْفِيَ اللهُ مِنْ نَفْسِي مَا هُوَ أَمْلَكُ بِهِ مِنِّي، فَإنَّمَا أَنَا وَأَنْتُمْ عَبِيدٌ مَمْلُوكُونَ لِرَبٍّ لاَ رَبَّ غَيْرُهُ

Therefore, do not abstain from saying a truth or pointing out a matter of justice because I do not regard myself above erring (1). I do not escape erring in my actions but that Allah helps me (in avoiding errors) in matters in which He is more powerful than I. Certainly, I and you are slaves owned by Allah


[Nahj-ul-Balagha, link for Arabic and English]


Here, we can see very clearly that Nawasib did not quote the complete sentence.

Researchers of the English translations wrote on this

That the innocence of angels is different from the innocence of man needs no detailed discussion. The innocence of angels means that they do not possess the impulse to sin, but the innocence of man means that, although he has human frailties and passions, yet he possesses a peculiar power to resist them and he is not over-powered by them so as to commit sins. This very ability is called innocence and it prevents the rising up of personal passions and impulses. Amir al-mu’minin’s saying that “I do not regard myself above erring” refers to those human dictates and passions, and his saying that “Allah helps me in avoiding ‘errors'” refers to innocence. The same tone is found in the Qur’an in the words of Prophet Yusuf that:

I exculpate not myself, verily (one’s) self is wont to bid (him to) evil, except such as my Lord hath had mercy on; verily my Lord is Oft- forgiving, All-merciful. (12:53)

Just as in this verse, because of the existence of exception, its firstpart cannot be used to argue against his innocence, similarly, due to the existence of the exception “but that Allah helps me in avoiding errors” in Amir al-mu’minin’s saying, its first part cannot be used to argue against his innocence, otherwise the Prophet’s innocence too will have to be rejected.

Apart from that, the narration has been taken from a sermon in Al Kafi, 8/352 ; as has been clarified by Syed Abdul Zahra al Husseini in his book Masadir Nahj-ul-Balagha wa Asaneedoha, 3/128

And this narration has been termed Daif  by Al Majlisi in his Miraat-ul-Uqool, 26/517

For more details, please refer to the reply of Sheikh Syed Hashim al Hashmi on this subject