Mistake in recitation which invalidates prayer
Question 2- Imam read in the fajr salat ( Surah Saffat ) Is the salat still valid ? Answer:
ﺑﺴﻢ اﷲ اﻟﺮﺣﻤﻦ اﻟﺮﺣﯿﻢ
In the name of Allah, the Most Gracious, the Most Merciful
In principle, if a person makes such a mistake in his recitation which excessively changes the meaning, then the prayer will be rendered invalid.1 As for the example you mentioned, the correct way to recite the verse is: Translation: “We are not going to die anymore  except our first death, nor will we be punished?  (Surah Saffat) In this verse Allah ﺗﻌﺎﻟﻰ quotes the statement of a person of Paradise, who is addressing his fellow Paradise denizens by way of expressing his happiness2 of there being no death in Paradise, hence the bounties will never cease, nor will they be punished. As for the sentence “ﺑﻤﺒﻌﻮﺛﯿﻦ ﻧﺤﻦ ﻣﺎ و” (we will not be resurrected), this is the statement of the disbelievers (which is mentioned in Surah Al-Anaam and Surah Al- Muminoon), based upon their false belief of there being no resurrection.
As for the Imam’s mistake, he substituted the statement of a believer (nor will we be punished) for the statement of a disbeliever (we will not be resurrected). It is obvious that a believer would never make such a statement, let alone a dweller of Paradise, hence based on the abovementioned principle (excessive change in meaning invalidates the prayer), the prayer will be considered null and void, and consequently the prayer should be repeated.
Only Allah knows best
Written by Maulana Mohammad Ahsan Osmani Checked and approved by Mufti Mohammed Tosir Miah Darul Ifta Birmingham
1 Munyatul Musalli wa Ghunyatul Mubtadi: p. 163 (Maktaba Tayyibah); Nur ul Idah (footnotes regarding slip of the Qari): p. 113 (Bushra); Raddul Muhtar: p. 393, v. 2 (Maktaba Imdadia) 2 Ma’ariful Quran: p. 61, v. 8 (Maktaba Rasheedia [Pashto translation])