[Machine] The Messenger of Allah ﷺ said: "If one of you prays and does not know if he has increased or decreased (in the prayer), then he should perform two prostrations while he is sitting, then he should offer the salutation. Abu Ali Al-Rudhbari informed us that Abu Bakr ibn Dasa narrated to us, Abu Dawood narrated to us, Hajjaj narrated to us, Ya'qub narrated to us, my father narrated to me from Ibn Ishaq, he said: Muhammad ibn Muslim Al-Zuhri informed me with his chain of transmission, and he said: "He should perform two prostrations before offering the salutation, then he should offer the salutation." And Ibn Ishaq mentioned another chain of transmission in it.  

أَنَّ رَسُولَ اللهِ ﷺ قَالَ إِذَا صَلَّى أَحَدُكُمْ فَلَمْ يَدْرِ أَزَادَ أَمْ نَقَصَ فَلْيَسْجُدْ سَجْدَتَيْنِ وَهُوَ جَالِسٌ ثُمَّ لِيُسَلِّمْ 3831 أَخْبَرَنَا أَبُو عَلِيٍّ الرُّوذْبَارِيُّ أنبأ أَبُو بَكْرِ بْنُ دَاسَةَ ثنا أَبُو دَاوُدَ ثنا حَجَّاجٌ ثنا يَعْقُوبُ ثنا أَبِي عَنِ ابْنِ إِسْحَاقَ قَالَ حَدَّثَنِي مُحَمَّدُ بْنُ مُسْلِمٍ الزُّهْرِيُّ بِإِسْنَادِهِ وَقَالَ فَلْيَسْجُدْ سَجْدَتَيْنِ قَبْلَ أَنْ يُسَلِّمَ ثُمَّ يُسَلِّمُ وَلِابْنِ إِسْحَاقَ فِيهِ إِسْنَادٌ آخَرُ