If during prayers one doubts whether or not he performed a certain obligatory act of the prayer– for example, he doubts whether or not he recited Sūrat al-Ḥamd – then, in the event that he has started to perform an act that he must not legally (sharʿan) perform if he intentionally misses that previous act – for example, while reciting the other surah he doubts whether or not he recited Sūrat al-Ḥamd00 – in such a case, he must dismiss his doubt;[1] otherwise [i.e.
if he has not started to perform the other act], he must perform the act about which he doubts.