Does the prayer of an Imam become invalid if he is suddenly afflicted by ostentation (riya') during the prayer and succumbs to it, and is it incumbent upon him to discontinue the prayer and appoint someone else to lead?

If the origin of the act was for Allah's sake, and then showing off (riya') occurred: if it was a fleeting thought and he repelled it, it does not harm him. But if he indulged in it, does it invalidate the act or does it not harm him and he is rewarded for his original intention? Scholars have differed on this. Imam Ahmad and Ibn Jarir al-Tabari preferred the view that his act is not invalidated by it, and he is rewarded for his initial intention. They cite the hadith: "All of them, if the origin of their matter was that the word of Allah be the highest."

This difference applies to an act whose end is connected to its beginning, such as prayer. As for acts where there is no such connection, like recitation and dhikr, they are interrupted by the sudden intention of showing off and require a renewal of intention.

Accordingly, the Imam must resist showing off. If he indulges in it, he should not interrupt his prayer, because its invalidation is not agreed upon, and interrupting it would cause disruption to the congregants and might open the door to whisperings (waswas).