Is it obligatory for the Imam to repeat the Fajr prayer if he made a mistake in the verse "وَتَجْعَلُونَ رِزْقَكُمْ أَنَّكُمْ تُكَذِّبُونَ" (And you make your provision that you deny/disbelieve) and said "تصدقون" (you believe/affirm) instead of "تكذبون" (you deny/disbelieve)?

An unintentional mistake in reciting the Quran during prayer, other than Surat Al-Fatihah, does not invalidate the prayer or necessitate its repetition. This is the view of the majority of scholars. Imam Ahmad ibn Hanbal does not believe in the necessity of repeating the prayer for someone who prayed behind an Imam who made a mistake in recitation, or recited a letter not from the Quran, or mixed verses of mercy with verses of punishment. As for the Hanafis, they believe repetition is obligatory if the mistake significantly alters the meaning, or if there is no similar verse in the Quran. Therefore, if the Imam repeats the prayer, following the Hanafi school of thought, there is no blame on him or on the congregants, even though the preponderant view is that repetition is not necessary.