حَدَّثَنَا مُحَمَّدُ بْنُ سَلَمَةَ عَنْ خُصَيْفٍ عَنْ أَبِي عُبَيْدَةَ عَنْ أَبِيهِ عَبْدِ اللَّهِ بْنِ مَسْعُودٍ عَنْ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ إِذَا كُنْتَ فِي الصَّلَاةِ فَشَكَكْتَ فِي ثَلَاثٍ وَأَرْبَعٍ وَأَكْثَرُ ظَنِّكَ عَلَى أَرْبَعٍ تَشَهَّدْتَ ثُمَّ سَجَدْتَ سَجْدَتَيْنِ وَأَنْتَ جَالِسٌ قَبْلَ أَنْ تُسَلِّمَ ثُمَّ تَشَهَّدْتَ أَيْضًا ثُمَّ سَلَّمْتَ
مسند امام احمد بن حنبل · Hadith 4075
It was narrated from Abu 'Ubaidah, from his father 'Abdullah bin Mas'ood, that the Prophet (PBUH) said: "If you are praying and you are not sure whether you did three or four (rak'ahs), hut you think it most likely that you did four, then say the tashahhud, then do two prostrations when you are sitting, before you say the salam. Then say the tashahhud again, then say the salaui."
Sanad
حَدَّثَنَا مُحَمَّدُ بْنُ سَلَمَةَ عَنْ خُصَيْفٍ عَنْ أَبِي عُبَيْدَةَ عَنْ أَبِيهِ عَبْدِ اللَّهِ بْنِ مَسْعُودٍ