If the Imam makes a mistake while reciting an Ayah and then remembers after Ruku`
Q 2: I offered Tarawih (special supererogatory night Prayer in Ramadan) once behind an Imam (one who leads congregational Prayer). In one of the Rak`ahs (units of Prayer), he recited the part of Surah Al-Mutaffifin that states:
Nay! Truly, the Record (writing of the deeds) of the Fujjâr (disbelievers, polytheists, sinners, evil-doers and the wicked) is (preserved) in Sijjîn.
And what will make you know what Sijjîn is?
A Register inscribed.
Then he recited "which is witnessed by those brought near [to Allah]." However, the correct Ayah (Qur'anic verse) is
Woe, that Day, to those who deny.
He then performed Ruku` (bowing) during which he recognized his fault, although no one corrected him. He interrupted his Ruku`, stood up, and told the Ma'mums (people being led by an Imam in Prayer) that the Rak`ah is invalid, because he had drastically changed the meaning of the Ayah. He pronounced Takbir (saying: "Allahu Akbar [Allah is the Greatest]"), repeated the Rak`ah and continued the Salah (Prayer).Is what this Imam did correct? Is this Rak`ah invalid? (Part No. 5; Page No. 336) What should I do if it was actually invalid?
If the situation is as you mentioned,
what the Imam did was out of forgetfulness. Allah (Glorified and Exalted be He) pardons the Muslims for this. The Salah is valid, and it does not have to be repeated, whether the error is done by the Imam or anyone of the congregation. They should continue their Salah according to Allah's Statement:
Our Lord! Punish us not if we forget or fall into error
It was authentically reported that the Messenger of Allah (peace be upon him) said:
"Allah (Glorified be He) said (in response to the supplication in this Ayah), 'I have done.'"
May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.