Whenever one doubts whether or not he has pronounced a verse or a word correctly – for example, he doubts whether or not he recited قُلْ هُوَ اللهُ أَحَدٌ [qul huwal lāhu aḥad][1] correctly – he can ignore his doubt. However, if he repeats that verse or word in a correct manner as a precautionary measure, there is no problem; and even if he doubts it several times, he can repeat it several times. However, if it becomes obsessive, it is better not to repeat it.