Mustadrak al-Hakim 1210

Abū Bakr Aḥmad b. Isḥāq al-Faqīh And ʾAnbaʾ ʿAlī b. al-Ḥasan b. Bayān > ʿAbdullāh b. Rajāʾ > Ḥarb b. Shaddād > Yaḥyá b. Abū Kathīr > ʿIyāḍ > Saʾalt

I asked Abu Sa'id al-Khudri and said, "One of us prays but does not know how much he has prayed." He said, "The Messenger of Allah ﷺ said: If anyone of you prays and does not know how much he has prayed, he should prostrate two prostrations. And if Satan comes to anyone and says, 'You have prayed', let him say, 'I have not prayed,' except if he finds the smell of something or hear a sound with his ears."

حَدَّثَنَا أَبُو بَكْرٍ أَحْمَدُ بْنُ إِسْحَاقَ الْفَقِيهُ وَأَنْبَأَ عَلِيُّ بْنُ الْحَسَنِ بْنِ بَيَانَ ثنا عَبْدُ اللَّهِ بْنُ رَجَاءٍ أَنْبَأَ حَرْبُ بْنُ شَدَّادٍ أَنْبَأَ يَحْيَى بْنُ أَبِي كَثِيرٍ حَدَّثَنِي عِيَاضٌ قَالَ

سَأَلْتُ أَبَا سَعِيدٍ الْخُدْرِيَّ فَقُلْتُ أَحَدُنَا يُصَلِّي فَلَمْ يَدْرِ كَمْ صَلَّى قَالَ قَالَ رَسُولُ اللَّهِ ﷺ إِذَا صَلَّى أَحَدُكُمْ فَلَمْ يَدْرِ كَمْ صَلَّى فَلْيَسْجُدْ سَجْدَتَيْنِ وَإِذَا جَاءَ أَحَدَكُمُ الشَّيْطَانُ فَقَالَ إِنَّكَ قَدْ أَحْدَثْتَ فَلْيَقُلْ كَذَبْتَ إِلَّا مَا وَجَدَ رِيحًا بِأَنْفِهِ أَوْ سَمِعَ صَوْتًا بِإِذْنِهِ «هَذَا حَدِيثٌ صَحِيحٌ عَلَى شَرْطِ الشَّيْخَيْنِ وَلَمْ يُخَرِّجَاهُ»