Sahih Muslim Book - 5, Hadith - 1267

حَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى حَدَّثَنَا مُعَاذُ بْنُ هِشَامٍ حَدَّثَنِى أَبِى عَنْ يَحْيَى بْنِ أَبِى كَثِيرٍ حَدَّثَنَا أَبُو سَلَمَةَ بْنُ عَبْدِ الرَّحْمَنِ أَنَّ أَبَا هُرَيْرَةَ حَدَّثَهُمْ أَنَّ رَسُولَ اللَّهِ -صلى الله عليه وسلم- قَالَ « إِذَا نُودِىَ بِالأَذَانِ أَدْبَرَ الشَّيْطَانُ لَهُ ضُرَاطٌ حَتَّى لاَ يَسْمَعَ الأَذَانَ فَإِذَا قُضِىَ الأَذَانُ أَقْبَلَ فَإِذَا ثُوِّبَ بِهَا أَدْبَرَ فَإِذَا قُضِىَ التَّثْوِيبُ أَقْبَلَ يَخْطُرُ بَيْنَ الْمَرْءِ وَنَفْسِهِ يَقُولُ اذْكُرْ كَذَا اذْكُرْ كَذَا. لِمَا لَمْ يَكُنْ يَذْكُرُ حَتَّى يَظَلَّ الرَّجُلُ إِنْ يَدْرِى كَمْ صَلَّى فَإِذَا لَمْ يَدْرِ أَحَدُكُمْ كَمْ صَلَّى فَلْيَسْجُدْ سَجْدَتَيْنِ وَهُوَ جَالِسٌ ».

Abu Hurairah narrated that the Messenger of Allah (s.a.w) said: "When the Adhan is called, the Shaitan runs away breaking wind, so that he will not hear the Adhan. When the Adhan ends, he comes back. Then when the Iqamah is called, he runs away, then when it is over, he comes back and distracts a man saying, 'Remember such and such, remember such and such,' reminding him of things that he had not remembered, until the man does not know how many Rak'ah he prayed. If one of you does not know how many Rak'ah he has prayed, let him prostrate twice while he is sitting."