Clarifying the Waswasah (Whispers, Bad Thoughts) with regard to faith, and what the one who experiences that should say
حَدَّثَنَا هَارُونُ بْنُ مَعْرُوفٍ، وَمُحَمَّدُ بْنُ عَبَّادٍ، - وَاللَّفْظُ لِهَارُونَ - قَالاَ حَدَّثَنَا سُفْيَانُ، عَنْ هِشَامٍ، عَنْ أَبِيهِ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " لاَ يَزَالُ النَّاسُ يَتَسَاءَلُونَ حَتَّى يُقَالَ هَذَا خَلَقَ اللَّهُ الْخَلْقَ فَمَنْ خَلَقَ اللَّهَ فَمَنْ وَجَدَ مِنْ ذَلِكَ شَيْئًا فَلْيَقُلْ آمَنْتُ بِاللَّهِ " .
It is narrated on the authority of Abu Huraira that the Messenger of Allah (ﷺ) said: Men will continue to question one another till this is propounded: Allah created all things but who created Allah? He who found himself confronted with such a situation should say: I affirm my faith in Allah.