Sunan an-Nasa'i #1248 · The Book of Forgetfulness (In Prayer)

Sunan an-Nasa'iIt was narrated that Abdullah bin Ja'far said
Sunan an-Nasa'i · Book 13 · The Book of Forgetfulness (In Prayer)
Sunan an-Nasa'i · كتاب 13 · كتاب السهو
"The Messenger of Allah (ﷺ) said: 'Whoever has doubt during his prayer, let him prostrate twice after he has said the taslim
أَخْبَرَنَا سُوَيْدُ بْنُ نَصْرٍ، قَالَ أَنْبَأَنَا عَبْدُ اللَّهِ، عَنِ ابْنِ جُرَيْجٍ، قَالَ قَالَ عَبْدُ اللَّهِ بْنُ مُسَافِعٍ عَنْ عُتْبَةَ بْنِ مُحَمَّدِ بْنِ الْحَارِثِ، عَنْ عَبْدِ اللَّهِ بْنِ جَعْفَرٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏
"‏ مَنْ شَكَّ فِي صَلاَتِهِ فَلْيَسْجُدْ سَجْدَتَيْنِ بَعْدَ مَا يُسَلِّمُ ‏"‏ ‏.‏
Reference : Sunan an-Nasa'i 1248In-book reference : Book 13, Hadith 70