Arabic (Original)
حَدَّثَنَا يَزِيدُ بْنُ هَارُونَ أَخْبَرَنَا هِشَامٌ عَنْ يَحْيَى حَدَّثَنَا عِيَاضٌ أَنَّهُ سَأَلَ أَبَا سَعِيدٍ الْخُدْرِيَّ فَقَالَ إِنَّ أَحَدَنَا يُصَلِّي فَلَا يَدْرِي كَمْ صَلَّى فَقَالَ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ إِذَا صَلَّى أَحَدُكُمْ فَلَمْ يَدْرِ كَمْ صَلَّى فَلْيَسْجُدْ سَجْدَتَيْنِ وَهُوَ جَالِسٌ فَإِذَا جَاءَ أَحَدَكُمْ الشَّيْطَانُ فَقَالَ إِنَّكَ قَدْ أَحْدَثْتَ فِي صَلَاتِكَ فَلْيَقُلْ كَذَبْتَ إِلَّا مَا وَجَدَ رِيحًا بِأَنْفِهِ أَوْ سَمِعَ صَوْتًا بِأُذُنِهِ.
English Translation
Yazid ibn Harun told us: Hisham informed us, from Yahya - Iyad told us that he asked Abu Sa'id al-Khudri, saying, "One of us prays and does not know how much he has prayed." He said: The Messenger of Allah, peace and blessings be upon him, said, "When one of you prays and does not know how much he has prayed, let him prostrate two prostrations while sitting. And if Satan comes to one of you and says, 'You have invalidated your prayer,' let him say, 'You lie,' unless he finds a smell with his nose or hears a sound with his ear."